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Complete allele information in the diagnosis of facioscapulohumeral muscular dystrophy by triple DNA analysis.

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BRIEF COMMUNICATIONS
Molecular and Clinical
Correlation in Five Indian
Families with Spinocerebellar
Ataxia 12
Achal K. Srivastava, DM,1 Shweta Choudhry, MSc,2
Musuwadi S. Gopinath, MD,1 Sanghamitra Roy, MSc,2
Manjari Tripathi, DM,1 Samir K. Brahmachari, PhD,2,3
and Satish Jain, DM1
Spinocerebellar ataxia 12 (SCA12) is a recently identified
form of autosomal dominant cerebellar ataxia associated
with the expansion of an unstable CAG repeat in the 5ⴕ
untranslated region of the gene PPP2R2B. We analyzed
77 Indian families with autosomal dominant cerebellar
ataxia phenotype and confirmed the diagnosis of SCA12
in 5 families, which included a total of 6 patients and 21
family members. The sizes of the expanded alleles ranged
from 55 to 69 CAG repeats, and the sizes of the normal
alleles ranged from 7 to 31 repeats. We believe our study
is the first to demonstrate that SCA12 may not be as rare
in some populations as previously thought.
Ann Neurol 2001;50:796 – 800
Autosomal dominant cerebellar ataxias (ADCAs) are a
genetically heterogeneous group of hereditary neurodegenerative disorders manifesting clinically in varying
degrees of brainstem and cerebellar pathology or dysfunction.1,2 The discovery of distinct disease-causing
genetic loci, which were previously defined on the basis
of clinical1,2 and pathological criteria,3 has led to the
genetic subgrouping of ADCAs into spinocerebellar
ataxia 1 (SCA1),4 SCA2,5 SCA3/Machado-Joseph disease (MJD),6 SCA6,7 SCA7,8 SCA8,9 SCA10,10
SCA12,11 SCA17,12 and dentatorubral pallidoluysian
atrophy (DRPLA).13 Various ADCAs are caused by the
abnormal expansion of trinucleotide repeat motifs in
their corresponding genes,4 –9, 11–13 except for SCA10,
which is due to a pentanucleotide (ATTCT) repeat expansion.10
From the 1Department of Neurology, Neurosciences Center, All India Institute of Medical Sciences, New Delhi, India; 2Functional
Genomics Unit, Center for Biochemical Technology (CSIR), Delhi,
India; and 3Molecular Biophysics Unit, Indian Institute of Science,
Bangalore, India.
Received May 9, 2001, and in revised form Aug 24. Accepted for
publication Aug 24, 2001.
Published online Nov 1, 2001; DOI 10.1002/ana.10048
Address correspondence to Dr Jain, Department of Neurology,
Neurosciences Center, All India Institute of Medical Sciences, New
Delhi, India 110 029. E-mail: satjain55@hotmail.com
796
© 2001 Wiley-Liss, Inc.
Recently, an expansion of CAG repeat in the 5⬘ untranslated region of the gene PPP2R2B, encoding a
brain-specific regulatory subunit of protein phosphatase
2A, has been found to be responsible for a novel form
of ADCA, termed SCA12.11 The expanded alleles contain 55 to 78 repeats, compared with 7 to 32 repeats in
normal chromosomes.11,14,15 SCA12 is rare,11,14,15 and
after its first description in a large American pedigree
of German decent by Holmes and colleagues,11 only
one more family, from India, has been identified so far
with SCA12 expansion.14 In this article, we report the
molecular and clinical features of SCA12 mutation in
five unrelated Indian families. In addition, we provide
information on the occurrence of SCA12 among Indian ADCA patients and report that SCA12 is not rare
in India.
Subjects and Methods
A total of 293 individuals from 77 ADCA families and 135
normal controls were studied. All probands and affected relatives were clinically examined by a team of neurologists and
were also subjected to nerve conduction studies and imaging
of the brain (computed tomography [CT] or magnetic resonance imaging [MRI]). ADCA type was diagnosed in accordance with standard criteria.2 Blood samples were collected
from all patients, normal relatives (who were also evaluated
clinically), and healthy controls. All participants gave informed consent and confidentiality was ensured. Parental
consent was obtained for minors. Some of these pedigrees
have been reported previously.16
DNA Isolation, Genotyping, and Sequencing Analysis
Genomic DNA was isolated from peripheral blood leukocytes using a modification of the salting-out procedure.17
The repeat-containing regions at SCA1,4 SCA2,5 SCA3/
MJD,6 SCA6,7 SCA7,18 SCA8,9 SCA12,11 and DRPLA13
loci were amplified by polymerase chain reaction (PCR) using previously published primers. The exact size of each repeat was determined by Gene Scan analysis using an ABI
Prism 377 automated DNA sequencer (Applied Biosystems,
Foster City, CA).
All of the expanded and a few normal SCA12 alleles were
analyzed by DNA sequencing. PCR products were generated
from genomic DNA using primer pair SCA12-FP (5⬘ TGGCCCTTAGCTGAGTGG 3⬘) and SCA12-RP (5⬘ TGCTGGGAAAGAGTCGTG 3⬘). Approximately 100ng of
genomic DNA was amplified in a 50␮l reaction volume containing a final concentration of 5mM Tris, 25mM KCl,
0.75mM MgCl2, 0.05% gelatin, 20pmol of each primer,
200␮M dNTPs, and 0.5 units of Taq DNA polymerase.
Samples were denatured at 94°C for 3 minutes followed by
35 cycles of denaturation (94°C, 30 seconds), annealing
(55°C, 30 seconds), extension (72°C, 30 seconds), and a final extension of 7 minutes at 72°C in a Perkin Elmer GeneAmp PCR System 9600 (Applied Biosystems, Foster City,
CA). The PCR products were purified from bands cut out of
agarose gel using a QIAquick gel extraction kit (Qiagen) and
were directly sequenced using the dideoxy chain terminator
chemistry on an ABI Prism 377 automated DNA sequencer
with the PCR primers.
Fig 1. Pedigrees of five Indian families affected by SCA12. Solid symbols represent affected status, symbols with a question mark
represent presymptomatic status (for individuals with CAG expansion who have not yet developed clinical symptoms), and open symbols represent unaffected status. For the 27 individuals who were actually examined and genotyped, the SCA12 CAG repeat allele
sizes and the age at disease onset are listed below their pedigree symbols.
Results
Frequency of SCA12 Mutation in Indian ADCA Patients
Among the 77 families studied, the SCA1 mutation was detected in 12 families (15.6%), SCA2
in 19 families (24.7%), SCA3/MJD and SCA7 in
2 families each (2.6%), and SCA12 in 5 families
(6.5%). None had expansion at SCA6, SCA8, or
DRPLA loci. The remaining 37 families (48%)
Srivastava et al: Indian Families with SCA12
797
Clinical Features
The clinical features of the Indian SCA12 patients included in this study are summarized in the table. Age
at onset of the disease ranged from 26 to 50 years
(mean, 37.2 years), and the duration of illness at the
time of examination varied from 3 to 13 years. All the
patients had gait ataxia and dysarthria. The initial
Fig 3. Gel electrophoresis of the fluorescence-labeled polymerase
chain reaction (PCR) products was conducted on an ABI
Prism 377 automated DNA sequencer (Applied Biosystems,
Foster City, CA) to determine the SCA12 CAG repeat sizes.
Normal alleles show sharp bands and no heterogeneity (bottom), whereas a range of products was observed in expanded
alleles (top), suggesting somatic mosaicism in the DNA derived
from peripheral blood leukocytes. The length of the expanded
allele was determined by the darkest (usually central) band,
which is flanked by one to three larger and smaller PCR
products of lighter intensities. The sizes of the CAG repeats in
all expanded and few representative normal alleles were also
confirmed by sequencing.
Fig 2. Distribution of CAG repeat at SCA12 locus in 270
normal chromosomes from 135 unrelated healthy controls. The
proportion of heterozygotes was 100 of 135 (74%).
were negative for expansion at all the loci studied.
Repeat Length Distribution of Normal and Expanded
SCA12 Alleles
The SCA12 CAG repeat region was amplified in 27
individuals (6 patients and 21 family members) from 5
genotypically confirmed SCA12 families (Fig 1) and
compared with 135 unrelated normal individuals. The
repeat size ranged from 7 to 31 repeats in normal individuals, with a heterozygosity of 74% (Fig 2). The
most common allele contained 10 CAG repeats constituting 48% of the normal chromosomes. Nine of the
27 individuals of SCA12 families showed expansion,
which included 6 patients and 3 asymptomatic at-risk
individuals (Fig 3). The expanded allele length in patients ranged from 55 to 69 and was 55, 55, and 66 in
3 asymptomatic individuals, AT047:II6, AT047:III2,
and AT089:II2 (see Fig 1).
Instability of expanded CAG repeats during transmission was studied in three parent-offspring pairs
(AT047:II4-III2, AT089:I1-II1, and AT089:I1-II2).
We observed a change of ⫺1(56 –55), ⫹2 (67– 69),
and ⫺1(67– 66) repeat units in the repeat size of the
expanded allele when transmitted from the affected
parent to the offspring. All the expanded alleles (n ⫽
9) and a few normal alleles (n ⫽ 40) were sequenced
to confirm the size and the internal structure of the
repeat. All the alleles analyzed possessed an uninterrupted CAG repeat configuration.
798
Annals of Neurology
Vol 50
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December 2001
Table. Clinical Features of Spinocerebellar Ataxia 12 Patients
Number of patients (families)
Women:men
Clinical features (n ⫽ 6)
Cerebellar gait ataxia
Dysarthria
Tremor in hands as initial symptom
Brisk reflexes
Extensor plantar
Eye signs
Slow saccades
Broken pursuit
Horizontal nystagmus
Facial myokymia
Axial dystonia
Dementia
Electrophysiological features (n ⫽ 6)
Subclinical sensory neuropathy
(absent sural SNAP)
Subclinical sensory-motor neuropathy (reduced CMAP and MNCV
and absent sural SNAP)
Imaging features (n ⫽ 6)
Cortical and cerebellar atrophy
(by CT/MRI)
6 (5)
1:5
6 (100%)
6 (100%)
4 (67%)
5 (83%)
2 (33%)
1 (17%)
2 (33%)
1 (17%)
2 (33%)
1 (17%)
0 (0%)
n (%)
2 (33%)
3 (50%)
5 (83%)
SNAP ⫽ sensory nerve action potential; CMAP ⫽ compound motor action potential; MNCV ⫽ motor nerve conduction velocity;
CT ⫽ computed tomography; MRI ⫽ magnetic resonance imaging.
symptom of the disease in 4 of our patients was tremor
in the hands, while the remaining 2 presented with gait
ataxia and dysarthria. Five of 6 had brisk reflexes and 2
patients had extensor plantar responses. Other symptoms were slow saccades, broken pursuits, horizontal
nystagmus, facial myokymia, and axial dystonia. None
of the patients had visual problems, ophthalmoplegia,
dysphagia, or dementia (“deranged” Mini Mental Status Examination score). Nerve conductions revealed
subclinical sensory neuropathy in 2 (absent sural sensory nerve action potential [SNAP]) and axonal sensory
motor neuropathy in three (reduced amplitude of compound motor action potential [CMAP], reduced motor
nerve conduction velocity [MNCV], and absent sural
SNAP), but were normal in 1 affected individual. Results of nerve conduction studies in 2 at-risk individuals were normal. Brain imaging (CT/MRI) was performed on all 6 affected patients and showed cerebellar
as well as cerebral cortical atrophy in 5, while the CT
scan was normal for the sixth patient (AT034:III7).
Correlation between Repeat Number and Age
at Onset
No apparent correlation was observed between the repeat size and the age at disease onset in SCA12 patients. Our observation is consistent with previous reports.11,14,19 However, in one parent-offspring pair,
the transmission of the disease allele from the father
AT089:I1 (disease onset at 50 years; repeat length n ⫽
67) to his affected son AT089:II1 (onset at 27 years;
repeat length n ⫽ 69) did accompany a decrease in age
at onset with an increase in the number of repeat units.
Contraction in the length of the expanded allele from
56 to 55 and from 67 to 66 was observed in the transmission of the disease allele from affected fathers
(AT047:II4 and AT089:I1, respectively) to their
asymptomatic children (AT047:III2 and AT089:II2).
As the latter are young (20 and 32 years) and still not
clinically affected, it is not possible to comment on the
consequence of this contraction on the age at onset at
this time.
Discussion
Our study demonstrates that SCA12 is not rare in India and accounts for approximately 7% of the ADCA
cases seen in our centre. The molecular study of
SCA12 families revealed a pathological CAG expansion
in all 6 affected individuals and in 3 asymptomatic individuals. The repeat sizes of the expanded alleles
ranged from 55 to 69 repeat units and were unstable
during transmission from parents to offspring. However, the instability was restricted to few repeat unit
changes (⫺1 to ⫹2 repeat units). In contrast to other
CAG repeat disorders20 in which expansions are more
common than contractions, in our SCA12 families
contractions (in two of the three vertical transmissions)
were observed more frequently. Furthermore, an inverse correlation between increasing repeat size and earlier age at disease onset, a characteristic of triplet repeat
disorders,20 was also not observed in our SCA12 patients.
The clinical features of our SCA12 patients are comparable to those described earlier11,14,19 and span the
full spectrum of ADCA type I except for optic atrophy.
Even in the presence of overt ataxia in all cases, 67% of
the patients reported hand tremor as the initial symptom. Oculomotor disturbances (in 3 of 6 patients), facial myokymia (in 2 of 6), and axial dystonia (in 1 of
6) were the other features we observed. In contrast to
previous reports,11,14,19 none of our patients had clinical evidence of dementia (2 patients aged 57 and 62
years had ataxia for over a decade), while 2 had facial
myokymia. Additionally, we found evidence of subclinical neuropathy in 5 of 6 patients. A clinical comparison of the SCA12 phenotype with other SCAs revealed
no specific signs that could consistently identify this
subtype, making genotyping essential for its accurate
diagnosis. In retrospect, we conclude that those ADCA
patients presenting with hand tremor in a setting of
milder ataxia, with brisk reflexes, evidence of subclinical peripheral neuropathy, and cerebral cortical and
cerebellar atrophy, can be suspected of having SCA12.
Srivastava et al: Indian Families with SCA12
799
Financial support from the Department of Biotechnology, Government of India, to S. K. Brahmachari of the Programme on Functional Genomics, is duly acknowledged. We thank Dr M. Mukerji
for scientific assistance and Ms R. Jaya, Ms Sakshi, Ms Manju, Ms
Gurjit, and Mrs Anuradha for technical support.
References
1. Harding AE. The clinical features and classification of the late
onset autosomal dominant cerebellar ataxias: a study of 11 families, including descendants of ‘the Drew family of Walworth.’
Brain 1982;105:1–28.
2. Harding AE. Clinical features and classification of inherited
ataxias. Adv Neurol 1993;61:1–14.
3. Konigsmark BW, Weiner LP. The olivopontocerebellar
atrophies: a review. Medicine (Baltimore) 1970;49:227–241.
4. Orr HT, Chung MY, Banfi S, et al. Expansion of an unstable
trinucleotide CAG repeat in spinocerebellar ataxia type 1. Nat
Genet 1993;4:221–226.
5. Pulst SM, Nechiporuk A, Nechiporuk T, et al. Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2. Nat Genet 1996;4:269 –276.
6. Kawaguchi Y, Okamoto T, Taniwaki M, et al. CAG expansion
in a novel gene for Machado-Joseph disease at chromosome
14q32.1. Nat Genet 1994;8:221–227.
7. Zhuchenko O, Bailey J, Bonnen P, et al. Autosomal dominant
cerebellar ataxia (SCA6) associated with small polyglutamine expansions in the alpha 1A-voltage-dependent calcium channel.
Nat Genet 1997;15:62– 69.
8. David G, Abbas N, Stevanin G, et al. Cloning of the SCA7
gene reveals a highly unstable CAG repeat expansion. Nat
Genet 1997;17:65–70.
9. Koob MD, Moseley ML, Schut LJ, et al. An untranslated CTG
expansion causes a novel form of spinocerebellar ataxia (SCA8).
Nat Genet 1999;21:379 –384.
10. Matasuura T, Yamagata T, Burgess DL, et al. Large expansion
of the ATTCT pentanucleotide repeat in spinocerebellar ataxia
type 10. Nat Genet 2000;26:191–194.
11. Holmes SE, O’Hearn EE, McInnis MG, et al. Expansion of a
novel CAG trinucleotide repeat in the 5⬘ region of PPP2R2B is
associated with SCA12. Nat Genet 1999;23:391–392.
12. Nakamura K, Jeong SY, Uchihara T, et al. SCA17, a novel
autosomal dominant cerebellar ataxia caused by an expanded
polyglutamine in TATA-binding protein. Hum Mol Genet
2001;10:1441–1448.
13. Koide R, Ikeuchi T, Onodera O, et al. Unstable expansion of
CAG repeat in hereditary dentatorubral-pallidoluysian atrophy
(DRPLA). Nat Genet 1994;6:9 –13.
14. Fujigasaki H, Verma IC, Camuzat A, et al. SCA12 is a rare
locus for autosomal dominant cerebellar ataxia: a study of an
Indian family. Ann Neurol 2001;49:117–21.
15. Worth PF, Wood NW. Spinocerebellar ataxia type 12 is rare in
the United Kingdom. Neurology 2001;56:419 – 420.
16. Saleem Q, Choudhry S, Mukerji M, et al. Molecular analysis of
autosomal dominant hereditary ataxias in the Indian
population: high frequency of SCA2 and evidence for a common founder mutation. Hum Genet 2000;106:179 –187.
17. Miller SA, Dykes DD, Polesky HF. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res 1988;16:1215.
18. Gouw LG, Castaneda MA, McKenna CK, et al. Analysis of the
dynamic mutation in the SCA7 gene shows marked parental
effects on CAG repeat transmission. Hum Mol Genet 1998;7:
525–532.
19. O’Hearn E, Holmes SE, Calvert PC, et al. SCA-12: tremor
with cerebellar and cortical atrophy is associated with a CAG
repeat expansion. Neurology 2001;56:299 –303.
800
© 2001 Wiley-Liss, Inc.
20. Cummings CJ, Zoghbi HY. Fourteen and counting: unraveling
trinucleotide repeat diseases. Hum Mol Genet 2000;9:
909 –916.
Reorganization of Somatic
Sensory Function in the
Human Thalamus After
Stroke
Shinji Ohara, MD, PhD,
and Frederick A. Lenz, MD, PhD
A patient with a thalamic stroke underwent a
microelectrode-guided stereotactic thalamic exploration
during surgery for control of tremor. The results of somatic sensory mapping in this patient were compared
with explorations carried out during stereotactic surgery
for the control of essential tremor (70 patients). There
was evidence both of somatotopic reorganization and of
anatomic reorganization of the representation of deep
structures in the principal somatic sensory nucleus of the
thalamus and the nuclei located anterior to it. This case
demonstrates that thalamic reorganization can occur after
a thalamic stroke and may play a role in recovery from
such a stroke.
Ann Neurol 2001;50:800 – 803
Reorganization of cortical function has been shown to
take place after a cortical stroke, and may be related to
functional recovery from strokes.1– 4 Subcortical lesions
also cause functional deficits, followed by substantial
recovery, perhaps due to changes in cortical function.5,6 However, the subcortical structure itself may
reorganize. We present results of a microelectrode exploration during thalamic surgery for tremor after an
ischemic thalamic stroke that demonstrated clear thalamic reorganization after the stroke.
Case Report
The patient was 59-year-old Caucasian man who experienced
sudden onset of a left hemiparesis and hemianesthesia due to
From the Department of Neurosurgery, Johns Hopkins Hospital,
Baltimore, MD
Received May 11, 2001, and in revised form Aug 28, 2001. Accepted for publication Aug 28, 2001.
Published online Nov 1, 2001; DOI: 10.1002/ana.10041
Address correspondence to Dr Lenz, Department of Neurosurgery,
Johns Hopkins Hospital, Meyer 7-113, 600 North Wolfe Street,
Baltimore, MD 21287-7713. E-mail: fal@pallidum.med.jhu.edu
an ischemic stroke. Magnetic resonance imaging and computed tomography showed an infarction in the right medial
temporo-occipital lobes and right posterior thalamus (Fig,
A). His initial symptoms, including anesthesia, abated, but
within a few weeks he developed tremor in his left hand that
did not respond to medical therapy.7–11
On examination, the patient had a left hemianopia, mild
left hemiparesis, and disabling tremor in the left upper extremity. His tremor occurred at rest as well as with posture
and action at a frequency of approximately 4Hz. Given the
failure of medical therapy, the patient was taken to the operating room for implantation of a thalamic stimulating
electrode for control of tremor. The procedure was terminated after the exploration and before implantation of
the electrode because it became clear that the area in which
the electrode would be implanted was involved with the
stroke.
Operative Procedures
The coordinates of thalamic nuclei were interpolated from
the coordinates of the anterior commissure–posterior commissure (AC–PC) line, as determined from a computed tomography scan. The target region was explored with the microelectrode, which was advanced along trajectories made
through a burr hole located 2.5cm lateral to the midline at
the level of the coronal suture. The first trajectory was toward the principal somatic sensory nucleus (ventral caudal,
Vc), because the response of cells in this area to somatic
stimulation was the most reliable physiological landmark for
the exploration.12 Next, the regions anterior to Vc, presumed
thalamic nuclei ventral intermediate and ventral oral posterior, were explored to identify the optimal site for implantation of the electrode.
Physiological exploration with the microelectrode involved
both recording of neuronal activity and stimulation at microampere current levels. Cells responding to somatic sensory
stimulation (sensory cells) were characterized by their response to stimulation of cutaneous or deep structures. Cutaneous sensory cells responded to touch or light pressure applied to the skin. Deep sensory cells responded to joint
movement or to squeezing of muscle or tendon, or both, but
they did not respond to stimulation of the skin deformed by
these stimuli. A reproducible response to repeated application of a stimulus in one part of the body was required to
identify a neuronal receptive field (RF).
Data Analysis
To demonstrate the unique distribution of sensory cells, we
reviewed a consecutive series of essential tremor (ET) patients undergoing stereotactic surgery (70 patients, 237 trajectories) as a control population. None of these patients was
found to have abnormalities on detailed somatic sensory examination. Deep or cutaneous RFs were used to identify the
body part represented by a cell. Separate body parts were
defined as intraoral structures, face, upper extremity, or
lower extremity, based on the distribution of sensory cells.13
Differences in proportions were tested statistically using a ␹2
or Fisher’s exact test, as appropriate.
Results
In the present case, sensory cells were recorded along
each of three trajectories in the 14mm lateral parasagittal plane. There were 19 sensory cells (9 deep and 10
cutaneous sensory cells) among a total of 83 cells recorded in this patient (see Fig, B). In the 70 ET patients, a total of 4,088 cells were identified along 237
trajectories. The location of recordings in thalamus was
verified by the presence of thalamic neuronal bursting
firing pattern for cells.14 It was not possible to distinguish the discharge patterns in this patient from those
in the controls given this small number of cells in our
patient. We first examined the location of deep sensory
cells relative to the AC–PC line. The distribution of
deep sensory cells above the AC–PC line in the present
case was 5 of 9 (56%); significantly different ( p ⫽
0.04) from that in the ET patients 476 of 563 (85%).
The proportion of all cells that were located above the
AC–PC line was not different ( p ⫽ 0.09) between our
case (62 of 83; 74%) and the ET patients (3361 of
4088; 82%). Therefore, the proportion of deep sensory
cells above the AC–PC line was significantly lower in
the present case than in controls.
Along the most posterior trajectory in the case (see
Fig, B), 11 sensory cells were identified; the RFs of
these cells together included all four body parts (ie, intraoral structures, face, upper extremity, and lower extremity). Along 237 trajectories in 70 control patients
with ET, however, 47% (112 of 237), 35% (84 of
237), and 8% (20 of 237) of trajectories had one, two,
and three of four body parts represented in the RFs of
deep and cutaneous sensory cells recorded along a trajectory. Trajectories with no RFs comprised 9% (21 of
237), but trajectories with RFs including all four body
parts were never found in this sample. Therefore, the
proportion of trajectories with four body parts represented was significantly higher in the stroke patient (1
of 3) than in control ET patients (0 of 237; p ⫽ 0.01).
Discussion
The present case of thalamic stroke demonstrates reorganization of thalamic maps based on comparison with
maps in 70 control patients with ET. RFs for cells located along one trajectory in the present case covered
all of four body parts, which was not observed in a
large control sample of ET patients (237 trajectories,
70 patients). The normal consistency of RFs along one
trajectory is due to the normal somatotopy of cutaneous and deep cells. Cells with cutaneous RFs are arranged into parasagittal sheets of cells, so that a trajectory in the parasagittal plane will usually encounter
cellular RFs located on one or two different parts of
the body.13 The representation of deep structures in
any part of the body parallels the cutaneous representation of those parts (see Fig 5 in Lenz et al13). Thus,
the representation of four body parts along a single tra-
Ohara and Lenz: Reorganization of Human Thalamus After Stroke
801
802
Annals of Neurology
Vol 50
No 6
December 2001
Š
Fig. (A) Axial T2-weighted magnetic resonance image shows an ischemic lesion in the right posterior thalamus. (B) Positions of the
trajectories (oblique lines) relative to the anterior commissure–posterior commissure (AC–PC) line (horizontal line). Locations of
cells and stimulation sites are indicated by tick marks to the right and left of each trajectory, respectively. Open circles ⫽ cutaneous
sensory cells; closed circles ⫽ deep sensory cells. (C) Projected and receptive fields for the sites identified in B. Each site where a
cell was recorded or stimulation was carried out is indicated by the same number in B and C. Threshold (in ␮A) is indicated below the projected field figurines. Bar in A is in centimeters.
jectory in the parasagittal plane (see Fig) is a dramatic
departure from normal thalamic somatotopy.
These results also suggest that the location of cells
with deep RFs has been shifted to a position inferior to
the usual location of such cells. These results could result from physical distortion of the thalamus resulting
from the stroke. However, it is more likely that the
somatic sensory nucleus and the nuclei anterior to it
have reorganized as a result of the stroke. To our
knowledge, this is the first report of single neuron analysis demonstrating functional reorganization in the primate thalamus after a thalamic stroke.
It has been reported that thalamic sensory organization is modified by interruption of sensory input.14 –17
The thalamic reorganization resulting from the thalamic damage has been previously reported in only 2
patients without either a description of lesions or a microelectrode analysis in the region of the stroke.8 The
relationship between thalamic reorganization and cortical reorganization is inextricable due to reciprocal
connections of these structures. Studies using positron
emission tomography in patients with a subcortical
stroke assume that the function in the subcortical
structures is taken over by related cortical areas.5,6 Recovery from motor stroke due to striatal–capsular infarction is associated with bilateral activation of the
cortical motor system, with use of ipsilateral pathways
and recruitment of additional cortical sensorimotor areas.5 The hemiplegia after ischemic infarction in the
basal ganglia and the thalamus is reported to recover in
parallel with the activation in the ipsilateral sensorimotor cortex.6 Therefore, cortical reorganization is an important aspect of recovery from subcortical strokes.
However, the present case demonstrates that thalamic
reorganization may also play a role in recovery from
thalamic strokes.
This work was supported by the National Institutes of Health
(NS38493 and NS40059 to F.A.L.).
We thank L. H. Rowland for excellent technical assistance.
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13. Lenz FA, Dostrovsky JO, Tasker RR, et al. Single-unit analysis
of the human ventral thalamic nuclear group: somatosensory
responses. J Neurophysiol 1988;59:299 –316.
14. Lenz FA, Kwan HC, Martin R, et al. Characteristics of somatotopic organization and spontaneous neuronal activity in the
region of the thalamic principal sensory nucleus in patients
with spinal cord transection. J Neurophysiol 1994;72:1570 –
1587.
15. Garraghty PE, Kaas JH. Functional reorganization in adult
monkey thalamus after peripheral nerve injury. Neuroreport
1991;2:747–750.
16. Rasmusson DD. Changes in the response properties of neurons
in the ventroposterior lateral thalamic nucleus of the raccoon
after peripheral deafferentation. J Neurophysiol 1996;75:
2441–2450.
17. Lenz FA, Zirh AT, Garonzik IM, et al. Neuronal activity in the
region of the principle sensory nucleus of human thalamus
(ventralis caudalis) in patients with pain following amputations.
Neuroscience 1998;86:1065–1081.
1. Castro-Alamancos MA, Borrel J. Functional recovery of forelimb response capacity after forelimb primary motor cortex
damage in the rat is due to the reorganization of adjacent areas
of cortex. Neuroscience 1995;68:793– 805.
Ohara and Lenz: Reorganization of Human Thalamus After Stroke
803
Evidence for Postjunctional
Serotonin (5-HT1) Receptors
in the Trigeminocervical
Complex
Peter J. Goadsby, MD, DSc, Simon Akerman, MSc,
and R. James Storer, PhD
Units linked to stimulation of the superior sagittal sinus
were identified and recorded from in the trigeminocervical complex of the anesthetized cat. Iontophoresis of glutamate NMDA receptor agonists increased the baselinefiring rate of these neurons. Coejection of sumatriptan,
4991W93, or ergometrine resulted in a significant reduction in NMDA agonist-induced increases in firing. These
data establish the existence of triptan-sensitive (5-HT1)
receptors on postsynaptic central trigeminal neurones.
Ann Neurol 2001;50:804 – 807
The pain in primary headache syndromes, such as migraine and cluster headache, is transmitted via the ophthalmic (first) division of the trigeminal nerve from
pain-producing intracranial structures, such as the dura
mater and large vessels, projecting to the trigeminocervical complex.1 Modulation of pain transmission by
triptans, 5-HT1B/1D receptor agonists, formed an important advance in treatment,2 offering clarification of
potential pharmacological mechanisms involved in terminating these attacks.3 A key question in understanding the mechanism of action of these compounds is
their site of action.
One proposed site of action for triptans is within the
trigeminocervical complex.3 It has been assumed, based
on observations of inhibition of plasma protein extravasation,4 and because of the localization of 5-HT1D
mRNA in the trigeminal ganglion,5 that triptans block
trigeminal transmission by a prejunctional mechanism.
However, this has never been tested. It has been shown
that some component of transmission across the trigeminal nucleus involves glutamatergic mechanisms.6 – 8 In the current study we exploited the fact
that microiontophoretic application of NMDA receptor agonists can excite trigeminal neurons locally and
From the Headache Group, Institute of Neurology, The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
Received Mar 27, 2001, and in revised form Sep 4. Accepted for
publication Sep 4, 2001.
Published online Nov 5, 2001; DOI: 10.1002/ana.0274R
Address correspondence to Dr Goadsby, Institute of Neurology, Queen
Square, London WC1N 3BG UK. E-mail: peterg@ion.ucl.ac.uk
804
© 2001 Wiley-Liss, Inc.
thus directly override any prejunctional inhibitory effect of triptans, allowing direct examination of the
functional localization of 5HT1 receptors in the trigeminocervical complex.
Materials and Methods
All studies reported were conducted and terminated under
general anesthesia in accordance with a project license issued by the Home Office of the United Kingdom under
the Animals (Scientific Procedures) Act 1986. Five cats
weighing 3.3 ⫾ 0.4kg (mean SD) were anesthetized with
␣-chloralose (60mg/kg ip; Sigma, St. Louis, MO) and prepared for physiological monitoring. Halothane (May &
Baker-Rhone-Poulenc, Dagenham, UK/Fluothane, Zeneca,
Macclesfield, UK) (0.5–3% in a 40% oxygen/air mixture)
was administered during surgical procedures and then discontinued during experimental protocols.9 Core temperature was monitored and maintained using a rectal thermistor probe and a homeothermic heater blanket system
(Harvard Apparatus, Holliston, MA). Cats were intubated
and ventilated with a 40% oxygen/air mixture (Harvard
Apparatus); end-tidal CO2 and expired oxygen were continuously monitored (Datex-Ohmeda, Helsinki, Finland).
The depth of anesthesia was examined periodically by testing for sympathetic (pupillary and cardiovascular) responses
to noxious stimulation and withdrawal reflexes in the absence of neuromuscular blockade.
Stimulation and Recording
The superior sagittal sinus (SSS) was isolated for stimulation and supramaximally stimulated (20 –28V, 250 ␮sec,
0.1–1.0Hz) after neuromuscular blockade with gallamine
triethiodide (Concord, Essex, UK) (initially 10 –15mg/kg
IV maintained with 5–10mg/kg/hr).10 Extracellular recordings were made using a microiontophoretic combination
electrode consisting of seven-barreled glass pipette incorporating a central tungsten-recording electrode with an exposed recording tip length of approximately 12␮m.11 The
electrode was advanced or retracted in the cord substance
using a microdrive (Kopf Instruments, Tujunga, CA, or
Burleigh Instruments, NY). Signal from the recording electrode was fed via a preamplifier (1,000) (Neurolog, Digitimer, Herts, UK) through a 50Hz noise eliminator (Humbug, Quest Scientific, North Vancouver, BC) and neurolog
filter (bandwidth 300Hz to 10kHz) to a second stage variable amplifier then via a window discriminator and A/D
converter to a microcomputer where the signal was processed. The receptive fields of the units were characterized
as nociceptive specific (NS) if they responded to noxious
mechanical stimuli (such as pinch or pricking with a needle) or wide dynamic range (WDR) if they responded to
both.12 A microiontophoresis current generator (Dagan
6400, Dagan Corporation, Minneapolis, MN) provided the
current for ejecting test substances from the barrels. Retaining and balancing currents were used routinely.13
At the end of the experiment selected sites were marked
with an electrolytic lesion made by passing a 20 to 25␮A
cathodal current through the recording electrode for 20 to
30 seconds.
Fig 1. Inhibition of DL-H excitation by
sumatriptan. DL-H was applied continuously at 4nA. Cell firing was suppressed
during pulses of sumatriptan at ⫹50nA
(bars). Firing rate (ordinate, Hz) is plotted in 1-second bins on the abscissa (time,
seconds).
Drugs
The 4991W93, 4S[3-(trans-3-dimethylamino-cyclobutyl)1H-indol-5-yl methyl] oxazolidin-2-one, and sumatriptan
were obtained from GlaxoWellcome Research and Development (Stevenage, UK). Micropipette barrels used for iontophoresis of test substances were filled with 1.0M DLhomocysteate (DL-H), pH 8.0 (ICN, Pharmaceuticals); 1.0
M L-glutamate, monosodium, pH 8.0 (Sigma), 50mM ergonovine (ergometrine) maleate, pH 4.0 (Sigma),
sumatriptan, and 4991W93; saline (as a control).
Statistical Analysis
Summary data are presented as the mean standard error of
the mean. Neuronal responses to the test compound in each
animal were compared with baseline firing rates using the
critical ratio test.14 Population effects of compounds were
tested using the Mann-Whitney U test using a level of significance of p ⬍ 0.05 (SPSS version 9.0).
Results
Animals from which data are reported had cardiorespiratory parameters that were normal for the anesthetized
cat. Blood gas parameters were measured at intervals
throughout the experiment and were within normal
limits: arterial blood pH 7.38 ⫾ 0.04 and pCO2
3.40 ⫾ 0.89kPa.
Neuronal Characteristics
Cells were located 0mm to ⫺4mm caudal to the midpoint C2 rootlets, 0 to 300␮m lateral to the dorsal root
entry zone at a depth of ⫺700␮m to ⫺2,000␮m below the (dorsal) cord surface. Cells responded to superior sagittal sinus (SSS) stimulation with latencies consistent with 〈␦ fibers (8 –10ms). All neurones reported
were classified as wide dynamic range (WDR).
Baseline Characteristics and Effect of Excitatory
Amino Acids
Neurones responding to electrical stimulation of the
SSS were identified. They responded with a firing rate
of 15 spikes/50 stimuli. Microiontophoresis of DL-H
increased firing of neurones linked to SSS from a baseline of 13.6 ⫾ 1.4/sec to 50.2 ⫾ 5.6/sec (n ⫽ 10; p ⬍
0.01). Microiontophoresis of L-glutamate increased firing of neurones linked to SSS from a baseline of
0.48 ⫾ 0.06/sec to 27.9 ⫾ 2.4/sec (n ⫽ 5; p ⬍ 0.01).
Effect of 5HT1B/1D Agonists
Iontophoresis of sumatriptan during continued ejection
of DL-H resulted in a reduction in firing rate from
54.3 ⫾ 2.9 to 29.8 ⫾ 4.2/sec (n ⫽ 5; p ⬍ 0.05; Fig
1). Similarly, ejection of 4991W93 (Fig 2) produced a
prompt reduction in firing of trigeminal neurones.
Ejection of the ergot alkaloid ergometrine resulted in a
dose-dependent reduction in firing from a control level
of 46.1 ⫾ 4.6/sec to 30.8 ⫾ 4.5/sec at a current of
180nA (n ⫽ 5; p ⬍ 0.05; Fig 3).
Discussion
This study demonstrates that microiontophoresis of the
glutamate receptor agonists DL-homocysteate (DL-H) or
L-glutamate into the region of the trigeminal neurones
can activate cells also linked to stimulation of the superior sagittal sinus. Furthermore, while being activated
by glutamate receptor agonists, ejection of ergometrine,
or the triptans, sumatriptan or 4991W93, inhibited
neuronal activation. Given that DL-H and L-glutamate
were exogenously supplied, and can thus override any
prejunctional blockade of transmitter release, it can be
suggested that each of ergometrine, sumatriptan, and
4991W93 may have postsynaptic actions within the
trigeminal nucleus. If this is correct then postsynaptic
trigeminal neurones are likely to contain one or more
of 5-HT1B, 5-HT1D or 5-HT1F receptors to mediate
this action.
Triptans, which are serotonin 5HT1B/1D receptor
agonists, inhibit evoked trigeminovascular nociceptive
activity in the trigeminocervical complex. Each of
Goadsby et al: Postjunctional 5-HT Receptors
805
Fig 2. Inhibition of DL-H excitation by
4991W93. DL-H was applied continuously
at 4nA. Cell firing was suppressed during
pulses of 4991W93 microiontophoresis at
⫹50nA (bars). Firing rate (ordinate, Hz)
is plotted in 1-second bins on the abscissa
(time, seconds).
sumatriptan, after blood-brain barrier disruption, eletriptan, naratriptan, rizatriptan, 4991W93, and zolmitriptan, block evoked trigeminal nucleus activity.3 Furthermore, serotonin itself inhibits trigeminovascularly
evoked nociceptive responses in the caudal trigeminal
nucleus.15 Triptans and serotonin are effective acute
antimigraine treatments.2 It has been assumed that
triptans act on a prejunctional 5HT1 receptor whose
definitive characteristics are yet to be determined.
However, the cited intravenous studies cannot define
the localization of the putative triptan receptor.
Iontophoretic application of a triptan16 can localize
the effect to the second order trigeminal synapse. However, for spontaneously active and sagittal sinus-evoked
responses, it cannot differentiate pre- and postsynaptic
blockade. The new data effectively eliminate the possibility of a presynaptic effect by supplying the transmitter exogenously. This suggests that some component of
the inhibition is likely to be postsynaptic, although it
remains a distinct possibility that both pre- and
postsynaptic modulation is taking place. This conclusion is analogous to the prejunctional arguments made
for the peripheral action of triptans in which it was
shown that sumatriptan would not block the effects of
exogenously supplied substance P,17 and thus was most
likely to be acting prejunctionally to block neurogenic
plasma protein extravasation. Experiments using direct
distension of the superior sagittal sinus18 similarly suggested that sumatriptan could block peripheral transmission without necessarily constricting blood vessels.19 It remains possible that the observed effect in
our study involves modulation of some other third site,
such as a modulatory neuron with facilitatory effects at
this synapse. No such neuron has been thus described,
and because the effects of microiontophoresis are limited by diffusion, the neuron at least would have to be
modulating the second order synapse in the trigeminal
nucleus.
In summary, data are presented that demonstrate activation of trigeminal neurons in the most caudal tri-
Fig 3. Inhibition of L-glutamate excitation
by ergometrine. L-glutamate was applied
in 10-second pulses at 50nA followed by
20-second periods of retaining current.
Cell firing was suppressed during ergometrine microiontophoresis (bars). The
suppression was dose dependent to the
maximum inhibition at ⫹180nA. Firing
rate (ordinate, Hz) is plotted in 1-second
bins on the abscissa (time, seconds).
806
Annals of Neurology
Vol 50
No 6
December 2001
geminal nucleus caudalis with nociceptive vascular input, from structures known to be pain-producing in
humans, by activation of glutamate receptors. Coiontophoresis of glutamate agonists, DL-homocysteate
or L-glutamate, with either of the 5HT1B/1D agonists,
sumatriptan and 4991W93, or the ergot alkaloid, ergometrine, resulted in inhibition of neuronal activation. These data are consistent with the view that there
are postsynaptic triptan-sensitive receptors in the trigeminal nucleus, while not excluding the presence of
presynaptic modulation. These receptors may be a target for antimigraine compounds, and their identity and
presence needs to be considered in any formulation of
the mechanism of action of triptans.
This work was supported by GlaxoWellcome and The Wellcome
Trust. PJG is a Wellcome Trust Senior Research Fellow.
We thank Paul Hammond and Michele Lasalandra for their excellent technical assistance.
This material was presented in abstract form at the Tenth International Headache Congress, June 29 to July 2, 2001, in New York.20
13. Bloom FE. To spritz or not to spritz: the doubtful value of
aimless iontophoresis. Life Sci 1974;14:1819 –1834.
14. Nagler J, Conforti N, Feldman S. Alterations produced by cortisol in the spontaneous activity and responsiveness to sensory
stimuli of single cells in the tuberal hypothalamus of the rat.
Neuroendocrinology 1973;12:52– 66.
15. Goadsby PJ, Hoskin KL. Serotonin inhibits trigeminal nucleus
activity evoked by craniovascular stimulation through a
5-HT1B/1D receptor: a central action in migraine? Ann Neurol
1998;43:711–718.
16. Storer RJ, Goadsby PJ. Microiontophoretic application of serotonin (5HT)1B/1D agonists inhibits trigeminal cell firing in the
cat. Brain 1997;120:2171–2177.
17. Buzzi MG, Moskowitz MA. The antimigraine drug,
sumatriptan (GR43175), selectively blocks neurogenic plasma
extravasation from blood vessels in dura mater. Br J Pharmacol
1990;99:202–206.
18. Kaube H, Hoskin KL, Goadsby PJ. Activation of the trigeminovascular system by mechanical distension of the superior sagittal sinus in the cat. Cephalalgia 1992;12:133–136.
19. Hoskin KL, Kaube H, Goadsby PJ. Sumatriptan can inhibit
trigeminal afferents by an exclusively neural mechanism. Brain
1996;119:1419 –1428.
20. Goadsby PJ, Akerman S, Storer RJ. Triptans can act postsynaptically in the trigeminal nucleus: a microiontophoretic
study. Cephalalgia 2001;21:285–286.
References
1. Goadsby PJ. The pathophysiology of headache. In: Silberstein
SD, Lipton RB, Solomon S, eds. Wolff’s headache and other
head pain. 7th ed. Oxford: Oxford University Press, 2001:57–72.
2. Ferrari MD. Migraine. The Lancet 1998;351:1043–1051.
3. Goadsby PJ. The pharmacology of headache. Prog Neurobiol
2000;62:509 –525.
4. Moskowitz MA, Cutrer FM. SUMATRIPTAN: a receptortargeted treatment for migraine. Annu Rev Med 1993;44:145–154.
5. Rebeck GW, Maynard KI, Hyman BT, Moskowitz MA. Selective 5 HT1D␣ serotonin receptor gene expression in trigeminal
ganglion: implications for antimigraine drug development. Proc
Natl Acad Sci USA 1994;91:3666 –3669.
6. Storer RJ, Goadsby PJ. Trigeminovascular nociceptive transmission involves N-methyl-D-aspartate and non-N-methyl-Daspartate glutamate receptors. Neuroscience 1999;90:1371–1376.
7. Mitsikostas DD, Sanchez del Rio M, Waeber C, et al. The
NMDA receptor antagonist MK-801 reduces capsaicin-induced
c-fos expression within rat trigeminal nucleus caudalis. Pain
1998;76:239 –248.
8. Mitsikostas DD, Sanchez del Rio M, Waeber C, et al. NonNMDA glutamate receptors modulate capsaicin induced c-fos
expression within trigeminal nucleus caudalis. Br J Pharmacol
1999;127:623– 630.
9. Storer RJ, Butler P, Hoskin KL, Goadsby PJ. A simple method,
using 2-hydroxypropyl-␤-cyclodextrin, of administering ␣-chloralose at room temperature. J Neurosci Meth 1997;77:49 –53.
10. Storer RJ, Akerman S, Connor HE, Goadsby PJ. 4991W93, a
potent blocker of neurogenic plasma protein extravasation, inhibits trigeminal neurons at 5-hydroxytryptamine (5-HT1B/1D)
agonist doses. Neuropharmacology 2001;40:911–917.
11. Hellier M, Boers P, Lambert GA. Fabrication of a metal-cored
multi-barrelled microiontophoresis assembly. J Neurosci Meth
1990;32:55– 61.
12. Hu JW, Dostrovsky JO, Sessle BJ. Functional properties of
neurons in the cat trigeminal subnucleus caudalis (medullary
dorsal horn). I. Responses to oro-facial noxious and nonnoxious
stimuli and projections to thalamus and subnucleus oralis.
J Neurophysiol 1981;45:173–192.
Increased HTLV-I Proviral
Load and Preferential
Expansion of HTLV-I TaxSpecific CD8⫹ T Cells in
Cerebrospinal Fluid from
Patients with HAM/TSP
Masahiro Nagai, MD, PhD, Yoshihisa Yamano, MD, PhD,
Meghan B. Brennan, BA, Carlos A. Mora, MD,
and Steven Jacobson, PhD
To date, high human T-cell lymphotropic virus type I
proviral load in patients with human T-cell lymphotropic
virus type I-associated myelopathy/tropical spastic para-
From the Viral Immunology Section, Neuroimmunology Branch,
National Institute of Neurological Disorders and Stroke, National
Institutes of Health, Rockville Pike, Bethesda, MD 20892.
Received Apr 13, 2001, and in revised form Sep 4, 2001. Accepted
for publication Sep 4, 2001.
Published online Nov 2, 2001; DOI 10.1002/ana.10065
Address correspondence to Dr Jacobson, Viral Immunology Section,
Neuroimmunology Branch, National Institute of Neurological
Disorders and Stroke, National Institutes of Health, Building
10, Room 5B-16, 9000 Rockville Pike, Bethesda, MD.
E-mail: jacobsons@ninds.nih.gov
© 2001 Wiley-Liss, Inc.
807
paresis has been reported and is thought to be related to
the pathogenesis of human T-cell lymphotropic virus
type I-associated myelopathy/tropical spastic paraparesis.
However, the proviral load in cerebrospinal fluid has not
been well investigated. We measured human T-cell lymphotropic virus type I proviral load in cerebrospinal
fluid cells from human T-cell lymphotropic virus type
I-associated myelopathy/tropical spastic paraparesis patients using real-time quantitative polymerase chain reaction (TaqMan). Human T-cell lymphotropic virus type I
proviral load in cerebrospinal fluid cells were significantly higher than that of the matched peripheral blood
mononuclear cells, and a high ratio of human T-cell lymphotropic virus type I proviral load in cerebrospinal fluid
cells to peripheral blood mononuclear cells were observed
in patients with short duration of illness. Human T-cell
lymphotropic virus type I Tax-specific CD8ⴙ T cells, as
detected by peptide-loaded HLA tetramers, accumulated
in cerebrospinal fluid compared with that in peripheral
blood mononuclear cells, while the frequency of
cytomegalovirus-specific CD8ⴙ T cells in cerebrospinal
fluid was reduced. These observations suggest that accumulation of both human T-cell lymphotropic virus type
I-infected cells and preferential expansion of human
T-cell lymphotropic virus type I-specific CD8ⴙ cells in
cerebrospinal fluid may play a role in the pathogenesis of
human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis.
Ann Neurol 2001;50:807– 812
Human T-cell lymphotropic virus type I (HTLV-I) is
an exogenous human retrovirus responsible for the progressive neurological disease, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP).1,2
The vast majority of people infected with HTLV-I are
clinically asymptomatic, and less than 5% of those infected develop HAM/TSP. It has been suggested that
virus–host interactions play a role in this inflammatory
neurological disease. Newly adapted real-time quantitative polymerase chain reaction (PCR) approaches have
supported the observations that HTLV-I proviral loads
in peripheral blood mononuclear cells (PBMC) from
HAM/TSP patients were higher than those of HTLV-I
asymptomatic carriers; thus, these high proviral loads
have been related to the pathogenesis of this disorder.3– 6 However, the HTLV-I proviral load in cerebrospinal fluid (CSF) from HAM/TSP patients remains to
be determined.
Experimental observations in the CSF are thought to
better reflect events in the central nervous system
(CNS) than can be achieved by analysis of peripheral
blood.7 HTLV-I virus,8 anti-HTLV-I antibodies,1,2
and HTLV-I-specific CD8⫹ cytotoxic T lymphocytes9,10 have been detected in CSF from HAM/TSP
patients and have provided insights into the viral immunological events in the CNS of affected patients. It
808
Annals of Neurology
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December 2001
was therefore of interest to determine the levels of
HTLV-I proviral loads in HAM/TSP CSF. In addition, immunological methods that measure HLArestricted virus-specific CD8⫹ T-cell responses to immunodominant epitopes of HTLV-I (tetramers)10 –12
were also used to determine whether these cells could
be detected in the CSF of patients with HAM/TSP.
We report that the level of HTLV-I proviral (tax)
DNA in CSF cells from HAM/TSP patients using realtime quantitative PCR techniques (TaqMan) was elevated in the CSF of HAM/TSP patients compared
with PBMC. Moreover, in patients from whom sufficient CSF cells could be obtained, the frequency of
HTLV-I-specific CD8⫹ cells were also elevated in the
CSF and appear to represent a virus-specific expansion.
Patients and Methods
Subjects and Sample Preparation
Peripheral blood and CSF were obtained from patients with
HAM/TSP by informed consent. The diagnosis of HAM/
TSP was assessed according to the World Health Organization guidelines.13 HTLV-I antibodies were present in the serum and in the CSF of all patients. Lumber punctures and
blood samples were performed after obtaining informed consent as part of a clinical protocol reviewed and approved by
the National Institutes of Health institutional review panel.
The characteristics of patients with HAM/TSP are summarized in Table 1. Peripheral blood was taken on the same day
that the CSF was collected. PBMC were isolated from peripheral blood samples on a density gradient, and CSF cells
were collected after CSF was spun at 1,500 rpm for 10 minutes. DNA was extracted from cells using spin columns
DNA extraction kit (Qiagen, Valencia, CA). Sufficient CSF
cells were obtained from HAM/TSP patients 7, 8, and 9,
permitting the identification of HTLV-I Tax11-19-specific
CD8⫹T-cell and CMV-pp65-specific CD8⫹ T cells as described below.
Quantitative Polymerase Chain Reaction
HTLV-I proviral load was measured using real-time quantitative PCR (TaqMan) as described previously.12 The amount
of HTLV-I proviral DNA was calculated by the following
formula:
copy number of HTLV-I (pX) per 100 cells
⫽ [(copy number of HTLV-I)/(copy number of ␤-actin/2)]
⫻ 100.
Identification of Tax11-19-Specific CD8⫹T-Cell and
CMV-pp65-Specific CD8⫹ T Cells
Analysis of antigen-specific CD8⫹ cells was performed using a phycoerythrin-conjugated Tax11-19 peptide (LLFGYPVYV) loaded HLA-A*0201 tetramer (provided by
NIAID MHC Tetramer Core Facility, Atlanta, GA, and National Institutes of Health AIDS Research and Reference
Reagent Program) or CMV-pp65(NLVPMVATV)-loaded
HLA-A*0201 tetramer (kindly provided from Dr. Mats Eng-
Table 1. Clinical Characteristics and HTLV-I Proviral Load of HAM/TSP Patients
Subject
Race/Origin
Age
(yr)
Sex
EDSSa
Duration
of Illness
(yr)
HAM-1
HAM-2
HAM-3
HAM-4
HAM-5
HAM-6
HAM-7
HAM-8
HAM-9
B/USA
W/USA
B/USA
B/USA
B/African
H/USA
B/Jamaican
B/Jamaican
W/USA
56
59
64
45
39
57
55
14
45
F
M
M
F
F
F
F
F
M
6
7
6
6
6.5
6.5
7.5
6.5
2.0
13
14
12
3
1
2
26
4
2
HTLV-I Proviral
Loadb
CSF
PBMC
Ratio
47.95
44.56
40.82
49.67
33.90
85.81
NT
NT
NT
30.00
24.41
22.93
24.19
10.49
20.16
26.47
27.67
24.12
1.6
1.8
1.8
2.1
3.2
4.3
—
—
—
EDSS ⫽ expanded disability status scale.
HTLV-I proviral load is expressed as the copy number of HTLV-I DNA per 100 cells. The ratio was calculated by (HTLV-I proviral load in
CSF)/(HTLV-I proviral load in PBMC).
a
b
HTLV-I ⫽ human T-cell lymphotropic virus type I; HAM/TSP ⫽ HTLV-I-associated myelopathy/tropical spastic paraparesis; CSF ⫽ cerebrospinal fluid; PBMC ⫽ peripheral blood mononuclear cells; W ⫽ Caucasian; B ⫽ black; H ⫽ Hispanic; NT ⫽ not tested.
strand, Uppsala University, Sweden). The cells were washed
and incubated with HLA-A2 tetramer, anti-CD4-FITC
(Caltag Laboratories, Burlingame, CA), and anti-CD8-TRICOLOR (Caltag Laboratories) monoclonal antibodies for 30
minutes at 4°C. The labeled cells were washed, followed by
flow cytometric analysis. HLA-DR, CD25 expression on
tetramer-positive cells was also measured as previously described.12
Results and Discussion
Table 1 presents the clinical characteristics of HAM/
TSP patients and HTLV-I proviral loads of matching
PBMC and CSF cells. In all patients, the HTLV-I proviral load in CSF cells was higher than that in PBMC.
The mean ⫾SEM and median copy numbers in CSF
were 50.45 ⫾ 7.44 (median 46.26), and those in
PBMC were 22.03 ⫾ 2.65 (median 23.56). This difference was statistically significant ( p ⫽ 0.0277, Wilcoxon signed-ranks test). This result is consistent with
previously published data reporting that the proportion
of HTLV-I Tax protein-expressing cells in the CSF
from HAM/TSP patients was higher than that in
PBMC.14 However, Puccioni-Sohler and colleagues15
measured higher proviral loads in the PBMC of HAM/
TSP patients in Brazil, as compared with those in the
CSF. These conflicting data may result from technical
differences since the Brazilian study measured HTLV-I
proviral loads using semiquantitative PCR methods
without normalization with a housekeeping gene.
In this present study, the ratio of HTLV-I proviral
load in the CSF compared with PBMC ranged from
1.6 to 4.3. Of interest is the observation that patients
who had relatively high ratios (⬎2) were all cases with
a short duration of illness and expanded disability status scale scores of ⬎6 (Table 1). This relative augmentation of HTLV-I proviral load in the CSF may therefore relate to disease pathogenesis in the CNS of
HAM/TSP patients, although it remains unclear
whether this high ratio is also observed in the early
stages of HAM/TSP with low expanded disability status scale and short duration of disease.
HTLV-I primarily infects CD4⫹ T cells, although
CD8⫹ T cells may also be an important in vivo reservoir.16,17 To exclude the possibility that the difference
in HTLV-I proviral load between CSF cells and
PBMC was merely attributable to proportional changes
of CD4⫹ T cells, the percentage of CD4⫹ and CD8⫹
cells in CSF and PBMC were evaluated by flow cytometry. The CD4⫹/CD8⫹ ratio in CSF did not differ
significantly compared with that of PBMC (data not
shown) as previously reported.18,19 As demonstrated in
HAM-6, the percentages of CD4⫹ and CD8⫹ cells in
CSF were 46.7% and 25.8%, respectively. The percentages in PBMC were 33.2% and 19.5%, respectively. Therefore, a change in the proportion of T-cell
subsets would not be sufficient to account for the approximate fourfold increase in HTLV-I proviral load.
This result suggests that HTLV-I-infected lymphocytes
may preferentially migrate into the CSF from peripheral blood, or HTLV-I-infected lymphocytes may selectively expand in this compartment. These two possibilities are not mutually exclusive. It has been demonstrated that HTLV-I can cross the blood–brain barrier
by migration of infected lymphocytes in vivo, which
has been associated with clonal expansion of HTLV-Iinfected cells in the CSF of patients with HAM/TSP.20
It has been suggested that CSF cells may reflect immunological events in CNS tissue.7 The expansion of
HTLV-I Tax11-19-specific CD8⫹ T cells in the CSF
of HAM/TSP patients9,10 have supported the hypothesis that these cells may be directly involved in the
pathogenesis of this disorder. However, it is unclear
whether this increase in HTLV-I Tax-specific CD8⫹
Nagai et al: HTLV-1 Infection in CSF of HAM/TSP
809
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Annals of Neurology
Vol 50
No 6
December 2001
Š
Fig. Accumulation of HTLV-I Tax11-19-specific CD8⫹ T cells in CSF. CSF and peripheral blood were collected from each HAM/
TSP patient on the same day. Isolated cells were stained with HTLV-I Tax11-19-Tetramer or CMV-pp65-Tetramer, and antiCD8 monoclonal antibody. The percentage represents tetramer-positive CD8⫹ cells in total CD8⫹ cells in PBMC or CSF cells. (A)
HAM-7. (B) HAM-8.
cells in the CSF of HAM/TSP patients was specific for
HTLV-I. This important question of virus-specific
T-cell expansion in the CSF was directly addressed by
comparing the frequency of HTLV-I Tax-specific
CD8⫹ T cells to the common CMV-specific CD8⫹
T-cell response in both CSF and PBMC from two
HAM/TSP patients from which sufficient CSF cells
could be obtained (HAM-7 and HAM-8). Both patients were HLA-A*0201 and had detectable CMVspecific CD8⫹ T cells as determined by HLA-A*0201/
CMV-pp65 peptide tetramers.21 There was an expansion in HTLV-I tax-specific CD8⫹ cells in the CSF
compared with PBMC from both HAM/TSP patients
tested (Fig). In PBMC, 2.83% and 1.78% of CD8⫹
cells were HTLV-I Tax11-19-specific from HAM-7
and HAM-8, respectively, and were consistent with
previous reports on tetramer-reactive cells in the peripheral blood of HAM/TSP patients.10 –12 In the CSF
of HAM-7 and HAM-8, this population of HTLV-I
tax11-19-specific CD8⫹ cells increased to 16.2% and
8.82%, respectively. Importantly, no such expansion of
CMV-specific CD8⫹ T cells was observed in the CSF
of these HAM/TSP patients (Fig 1A, B). CMV-pp65
reactive CD8⫹ cells were either absent or minimally
detected in this compartment. An additional HAM/
TSP patient (HAM-9) showed a similar tetramer profile. The frequency of HTLV-I tax11-19-specific
CD8⫹ cells in PBMC was 2.95% and increased to
12.84% in CSF cells while the frequency of CMVspecific CD8⫹ T cells in PBMC was 0.49% and that
in CSF cells was 0.44%.
It has been demonstrated that activated T cells migrate into the CNS, irrespective of antigen specificity;
however, only CNS antigen-specific cells are retained.22
To determine the proportion of activated cells within
these each virus-specific CD8⫹ T populations, HLA-DR
Table 2. Expression of Activated T-Cell Marker on
Antigen-Specific CD8⫹ T Cells
HAM-7
Tax-Tetramer⫹
CMV-Tetramer⫹
Total CD8⫹ cells
HAM-8
HLA-DR
CD25
HLA-DR
CD25
64.08
51.09
38.38
6.12
3.11
2.15
75.66
11.97
14.53
10.34
3.7
1.24
Data are percentages of expression. Tax-Tetramer⫹ ⫽ HTLV-I
Tax11-19-specific CD8⫹ T cells. CMV-Tetramer⫹ ⫽ CMV-pp65specific CD8⫹ T cells.
CMV ⫽ cytomegalovirus; HTLV-I ⫽ human T-cell lymphotropic
virus type I; HAM ⫽ HTLV-I–associated myelopathy.
and CD25 expression were evaluated as markers of
T-cell activation. The percentage expression of both
HLA-DR and CD25 on HTLV-I Tax-specific CD8⫹ T
cells in PBMC was higher than that on CMV-specific
CD8⫹ T cells in PBMC (Table 2). The increased expression of markers of T-cell activation on HTLV-I
Tax-specific CD8⫹ cells in the peripheral blood is consistent with the hypothesis that these cells may have a
selective advantage to migrate into the CSF of HAM/
TSP patients. Preferential expansion in the CSF may be
associated with the recognition of HTLV-I infected cells
in this compartment or the CNS and may therefore
contribute to the pathogenesis of this disease.
In this report, greater HTLV-I proviral loads in CSF
compared with those in PBMC from HAM/TSP patients, particularly in cases with short duration of illness, have been determined by real-time quantitative
PCR. The preferential expansion of HTLV-I Tax1119-specific CD8⫹ T cells in the CSF is consistent with
the hypothesis that HAM/TSP is an immunopathologically mediated disease associated with high HTV-I
proviral loads driving virus-specific immune responses,
which may be amenable to immunotherapeutic strategies that target the virus and/or HTLV-I antigenspecific T cells.
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2. Osame M, Usuku K, Izumo S, et al. HTLV-I associated myelopathy, a new clinical entity [letter]. Lancet 1986;1:1031–1032.
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paraparesis. Blood 1990;75:428 – 433.
5. Kira J, Koyanagi Y, Yamada T, et al. Increased HTLV-I proviral DNA in HTLV-I-associated myelopathy: a quantitative
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6. Nagai M, Usuku K, Matsumoto W, et al. Analysis of HTLV-I
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7. Mor F, Cohen IR. T cells in the lesion of experimental autoimmune encephalomyelitis. Enrichment for reactivities to myelin basic protein and to heat shock proteins. J Clin Invest 1992;
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1567–1573.
10. Greten TF, Slansky JE, Kubota R, et al. Direct visualization of
antigen-specific T cells: HTLV-1 Tax11–19-specific CD8(⫹) T
cells are activated in peripheral blood and accumulate in cerebrospinal fluid from HAM/TSP patients. Proc Natl Acad Sci U
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Spinocerebellar Ataxia Type
2 Presenting as Familial
Levodopa-Responsive
Parkinsonism
Din-E Shan, MD, PhD,1,3 Bing-Wen Soong, MD, PhD,1,3
Chen-Ming Sun, MD,2 Shwn-Jen Lee, PhD, PT,4
Kwong-Kum Liao, MD,1,3 and Ren-Shyan Liu, MD2
A genetic analysis identified 2 patients, approximately
one-tenth of our patients with familial parkinsonism,
who had expanded trinucleotide repeats in SCA2 genes.
The reduction of 18F-dopa distribution in both the putamen and caudate nuclei confirmed that the nigrostriatal
dopaminergic system was involved in parkinsonian patients with SCA2 mutation.
Ann Neurol 2001;50:812– 815
Familial parkinsonism occurs in about 2.8% of Chinese
patients.1 Specific genes responsible for familial parkinsonism include ␣-synuclein, parkin, and ␶ genes.2 The
mode of inheritance related to the ␣-synuclein gene mutation is autosomal-dominant, but it is now known to
be a rare cause of familial parkinsonism.
Genetic anticipation occurs in some families with
parkinsonism, suggesting involvement of an unstable
trinucleotide (CAG) repeat.3 Spinocerebellar ataxia
type 3 (SCA3) may present with L-dopa-responsive
parkinsonism.4 Noncerebellar symptoms are usually
mild in SCA6, but include parkinsonism.5 Recently, a
large family from northern Taiwan with a mutation at
the SCA2 locus was reported; some present with parkinsonism.6 SCA2 has expanded CAG repeats within
the range of 34 to 59 in chromosome 12q. In Taiwan,
the SCA2 mutation accounts for about 10.8% of
autosomal-dominant cerebellar ataxia.7 The SCA2 phenotype differs from those of SCA1 and SCA3, with its
higher frequencies of slowed ocular movements, postural and action tremor, myoclonus, and hyporeflexia.8
Parkinsonism with minor cerebellar deficits occurs.9
Patients may present with either a typical L-dopa-
From the 1Neurological Institute, and 2National PET/Cyclotron
Center, Taipei Veterans General Hospital, and 3Departments of
Neurology and 4Physical Therapy, National Yang-Ming University,
Taipei, Taiwan, ROC.
Received July 10, 2001, and in revised form Sep 7, 2001. Accepted
for publication Sep 8, 2001.
Published online Nov 1, 2001; DOI: 10.1002/ana.10055
Address correspondence to: Dr Shan, Neurological Institute, Taipei
Veterans General Hospital, Taipei, Taiwan 11217, Republic of
China. E-mail: deshan@vghtpe.gov.tw
812
© 2001 Wiley-Liss, Inc.
Table. Clinical Features, Gait Characteristics, and Simple
Ratios of Regional 18F-Dopa Uptake of Patients 1 and 2
Pt 1
Age at onset
Duration of illness
Symptoms at onset
First UPDRS subscale
IIIa
Last UPDRS subscale
III
Rest tremor of legs
Rest tremor of hands
Postural tremor of
hands
Action tremor of hands
Rigidity
Brisk tendon reflexes
Plantar reflexes
Ataxia
Dysmetria
Pursuit
Saccades
50
6 yr
Tremor of left
leg
7
Pt 2
50
9 yr
Tremor of both
legs
14
45
23
⫹⫹⫹
⫹⫹
⫹⫹
⫹⫹⫹
⫹
⫺
⫺
⫹⫹⫹
Left knee
Flexor responses
⫺
⫺
Intact
Slow and hypometric
Nystagmus
⫺
Autonomic dysfunction
⫺
Speed/off (cm/sec)
67.0 ⫾ 11.0
Speed/on (cm/sec)
107.9 ⫾ 7.6
Stride length/off (cm)
65.3 ⫾ 5.0
Stride length/on (cm)
100.8 ⫾ 6.1
Simple ratio
2.01
(left caudate)b
2.18
Simple ratio
(right caudate)b
1.53
Simple ratio
(left putamen)b
1.54
Simple ratio
(right putamen)b
⫺
⫹⫹
Left biceps/knee
Flexor responses
⫺
⫺
Intact
Slow and hypometric
⫹
⫺
110.7 ⫾ 6.8
126.1 ⫾ 4.4
123.9 ⫾ 7.5
127.4 ⫾ 4.0
2.02
1.96
1.85
1.75
a
The first UPDRS assessments were performed 1 year after onset in
both patients.
b
The simple ratios of the regional 18F-dopa uptake of the left and
right caudate nucleus and the left and right putamen to that of the
occipital cortex in the control subject are 2.75, 2.63, 2.76, and 2.52,
respectively.
UPDRS ⫽ Unified Parkinson’s Disease Rating Scale.
⫺ ⫽ absent; ⫹ ⫽ mild; ⫹⫹ ⫽ moderate; ⫹⫹⫹ ⫽ severe.
three cardinal features—rest tremor, rigidity, and bradykinesia–to be diagnosed as having parkinsonism. Genomic DNA
was isolated from the peripheral leukocytes, and a polymerase chain reaction (PCR) was performed using primers F-1
and R-1 for SCA2, as previously described.10,11 Patients with
a proven SCA2 gene expansion were selected for assessments
by the Unified Parkinson’s Disease Rating Scale (UPDRS),12
by gait analyses,13 and by 18F-dopa-positron emission tomography (PET) scanning.
Gait analyses were assessed both before and after a single
challenge dose of 200/50mg of L-dopa/benserazide. The data
were compared with those from 12 sporadic parkinsonian
patients of comparable age (mean 60.3 ⫾ 4.6 years) and duration of illness (mean 9.5 ⫾ 3.1 years).
For PET scanning, antiparkinson medication was stopped
for at least 12 hours and 100mg of carbidopa was given 90
minutes before injection. Static 18F-dopa-PET scanning was
performed on Scanditronix PC4096-15WB whole-body PET
scanner (Scanditronix, Sweden) 120 minutes after injection
of 185MBq of 18F-dopa.
Images converted to ANALYZE format (Biomedical Imaging Resources, Mayo Foundation, Rochester, MN) by MEDX
3.3 (Sensor Systems, Sterling, VA) were transformed into Talairach and Tournoux space14 by the SPM99 (Wellcome Department of Cognitive Neurology, London, UK) under Matlab (Mathworks, Natic, MA), using a 12-parameter linear
affine normalization and a further nonlinear iteration algorithms with a template image generated from a 45-year-old
healthy man. This template image was the control subject in
this study.
The region of interest (ROI) technique was applied to the
transaxial slice at the AC/PC line. A standardized template of
ROIs was made for defining bilateral caudate nuclei, putamina, and gray matter of occipital lobes in this transaxial slice,
according to the corresponding Talairach coordinates. This
standardized template of ROIs was then superimposed on
the images to compute mean regional radioactivity.
Semiquantitative analysis using simple ratios of regional
18
F-dopa uptakes was conducted, which were calculated from
the mean regional radioactivity for bilateral caudate nuclei
Fig 1. Family pedigrees of Patient 1 (A) and Patient 2 (B).
responsive parkinsonism or an atypical parkinsonism,
including pictures of ataxia or progressive supranuclear
palsy (PSP).6 To characterize these parkinsonian patients further, in relation to SCA2 gene mutations, we
conducted the following study.
Patients and Methods
Genetic screening for expanded CAG repeats in the SCA2
gene was performed in 23 parkinsonian patients from 19
families with familial parkinsonism, and in 2 patients with
postural tremor but with family members affected with parkinsonism. All patients were recruited from the approximately 800 patients with parkinsonism who were registered
in the Special Clinic for Movement Disorders of Taipei Veterans General Hospital. Each patient must have two of the
Shan et al: SCA2 and Familial PD
813
Fig 2. Transaxial view of 18F-dopa positron emission tomography (PET) images in Patient 1 (A), Patient 2 (B), a healthy subject
(C), and a standardized template of regions of interest (ROIs) superimposed on the healthy subject (D). Profound loss of putaminal
18
F-dopa uptake and, to a lesser extent, of caudate 18F-dopa uptake, occurred in both patients.
and putamina, respectively, divided by the gray matter of the
occipital cortex.
Results
Two patients with parkinsonian features were identified as having an expanded SCA2 gene with 36 and 37
CAG repeat numbers, respectively. Their clinical features are summarized in Table.
Patient 1, an ethnic Taiwanese woman, had tremors
of the left leg. Her mother had presented with a
trihexyphenidyl-responsive leg tremor at 54 years of age,
followed by gait disturbance, and expired at the age of
73 (Fig 1A). The tremor in Patient 1 spread to the right
leg 3 years after onset; she would occasionally feel hesitant when starting to walk. Her baseline UPDRS subscale III, walking speed, and stride length were comparable with those of controls (31.9, 68.8cm/sec, 76.2cm,
respectively). A single dose of L-dopa/benserazide produced a 27% improvement in UPDRS subscale III (vs.
44% in controls), a 65% improvement in walking speed
(vs. 26% in controls, p ⬍ 0.01 by Wilcoxon rank-sum
test), and a 53% improvement in stride length (vs. 19%
in controls, p ⬍ 0.01), confirming that she was responsive to L-dopa.
Patient 2, an ethnic Taiwanese man, had tremors of
both legs. His mother had presented with sinemetresponsive tremors at the age of 68, followed by gait
disturbance, and expired at 79 years old (see Fig 1B).
The leg tremor of Patient 2 was not suppressed by propranolol, but it disappeared after taking alcohol, trihexyphenidyl, or primidone. He had occasional shuffling and falling three years after the onset. His baseline
walking speed and stride length were better than those
of controls ( p ⬍ 0.01, by unpaired t test), confirming
his slower progression of motor disability. A single dose
of L-dopa/benserazide produced a 48% improvement
in UPDRS subscale III, a 14% improvement in walking speed, and a 3% improvement in stride length.
Surface electromyograms (EMGs) disclosed in the
right vastus medialis of both patients a 4-Hz rest
814
Annals of Neurology
Vol 50
No 6
December 2001
tremor, which disappeared on voluntarily changing of
the leg position. Motor conduction time was measured
by transcranial magnetic stimulation and showed a
slightly prolonged conduction time from the cerebral
cortex to the lumbar cord (20.3msec, normal
⬍17msec) in Patient 1, but normal conduction peripherally. The sympathetic skin response showed an absent
response in both palm and sole, and the normal pattern of R-R intervals variation was lost in patient 2.
Magnetic resonance imaging showed slight atrophy of
the cerebral cortex in Patient 2.
PET studies showed decreased 18F-dopa distribution
in the bilateral striatum of both patients (Fig 2). The
simple ratios of the regional 18F-dopa uptake of the
caudate nucleus or the putamen, respectively, to that of
the occipital cortex in both patients were lower than
those of the control (see Table).
Discussion
The results of this study confirm previous findings that
patients with a mutation at the SCA2 locus could
present with typical L-dopa-responsive parkinsonism
and with minimal cerebellar deficits.6,9 We identified 2
patients, approximately one-tenth of our population
with familial parkinsonism, who had expanded CAG
repeats with low repeat numbers. This is consistent
with the finding that parkinsonism occurs in patients
with a relatively low repeat number in the expanded
SCA2 genes.6 None of our patients presented with myoclonus, dystonia, or myokymia, which usually appears
in patients with a relatively high repeat number.15 Genetic anticipation occurred in both patients.
The classic 4 to 6 Hz rest tremor of Parkinson’s disease (PD) occurs mostly in both hands and is temporarily suppressed when the extremity is voluntarily activated.16 The pattern of the tremor in both of our
patients was similar to that of typical parkinsonian
tremor, except for the predominant leg distribution
and the good response to primidone and alcohol. The-
oretically, patients with lesions involving both the nigrostriatal dopaminergic system and the cerebellothalamic system may present with Holmes’ tremor, a lowfrequency rest and intention tremor.16 None of our
patients demonstrated the existence of intention
tremor. However, it is possible that, with the progression of their cerebellar deficit, their tremor pattern
might change.
We measured the 18F-dopa metabolism using the
striato-occipital ratio method, which is simple but as
sensitive as the method that measures the decarboxylation coefficient.17 The results confirmed that the nigrostriatal dopaminergic system was involved in both
patients with SCA2 mutation. Unlike previous PET reports in patients with sporadic PD, the caudate nucleus
was severely involved in both cases.18 Their pattern of
18
F-dopa distribution appeared similar to that found in
patients with PSP. This explained that some of the affected family members might present with a clinical
picture indistinguishable from PSP,6 and that our patients had start hesitation and falling early in the
course, features characteristic of PSP.
Although our case number was limited, some characteristic features appeared: (1) both had onset in their
fifties; (2) both started with a prominent 4-Hz rest
tremor of the legs; (3) the progression of motor disability was relatively slow; (4) both maintained a good
L-dopa-responsiveness; and (5) both showed a reduced
18
F-dopa distribution, not only in the putamen but in
the caudate nucleus as well. It would be difficult to
identify our patients among patients with sporadic PD,
based on the clinical features alone. Gwinn-Hardy and
colleagues6 described that their parkinsonian patients
could be distinguished by the absence of a rest tremor,
and the mildly broad-based gait; none of these features
existed in our patients. They could have had an asymmetric onset or an asymmetric 18F-dopa distribution,
just as sporadic PD patients had. Neither presented
with overt signs, indicating cerebellar dysfunction, except mild gaze-directed nystagmus in Patient 2. The
only hints were an unusual alcohol-responsive leg
tremor, and a mild slowing of the ocular saccades or
gait hesitation suggestive of PSP.
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confirmation of 14q CAG expansion. Ann Neurol 1995;38:
684 – 687.
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This work was supported by the National Science Council (NSC90-2314-B-075-059) from the ROC and Taipei Veterans General
Hospital (VGH-90-372).
We thank Ms Win-Yung Sheng for assistance in the statistical analysis.
References
1. Chia LG, Liu LH. Parkinson’s disease in Taiwan: an analysis of
215 patients. Neuroepidemiology 1992;11:113–120.
2. Vaughan JR, Davis MB, Wood NW: Genetics of parkinsonism:
a review. Ann Hum Genet 2001;65:111–126.
Shan et al: SCA2 and Familial PD
815
Complete Allele Information
in the Diagnosis of
Facioscapulohumeral
Muscular Dystrophy by
Triple DNA Analysis
Richard J. L. F. Lemmers, BSc,1 Peggy de Kievit,1
Michel van Geel, PhD,3 Michiel J.R. van der Wielen,1
Egbert Bakker, PhD,1 George W. Padberg, MD, PhD,2
Rune R. Frants, PhD,1
and Silvère M. van der Maarel, PhD1
Facioscapulohumeral muscular dystrophy is caused by
partial deletion of the D4Z4 repeat array on chromosome
4q35. Genetic diagnosis is based on sizing of this repeat
array, which is complicated by cross-hybridization of a
homologous polymorphic repeat array on chromosome
10 and by the frequent exchanges between these chromosomal regions. The restriction enzyme XapI optimizes the
diagnosis of facioscapulohumeral muscular dystrophy by
uniquely digesting 4-derived repeat units and leaving 10derived repeat units undigested, thus complementing
BlnI, which uniquely digests 10-derived repeat units. A
triple analysis with EcoRI, EcoRI/BlnI, and XapI unequivocally allows characterization of each of the four alleles, whether homogeneous or hybrid. This is particularly useful in the case of identical sized 4-derived and
10-derived arrays, in situations of suspected facioscapulohumeral muscular dystrophy with nonstandard allele
configurations, and for assignment of hybrid fragments
to their original alleles.
Ann Neurol 2001;50:816 – 819
Facioscapulohumeral muscular dystrophy (FSHD,
MIM 158900) is characterized by progressive weakness
and atrophy of facial and shoulder girdle muscles and a
gradual spread, variable in time, to abdominal and
foot-extensor muscles, followed by involvement of up-
1
From the Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden; 2Department of Neurology, University Medical Center Nijmegen, Nijmegen, The Netherlands; and
3
Department of Cancer Genetics, Roswell Park Cancer Institute,
Buffalo, NY.
Current address for Dr van Geel: Department of Dermatology, University Medical Center Nijmegen, P.O Box 9101, 6500 HB, The
Netherlands.
Received May 21, 2001, and in revised form Sep 10, 2001. Accepted for publication Sep 10, 2001.
Published online Nov 5, 2001; DOI 10.1002/ana.10057
Address correspondence to Dr van der Maarel, Leiden University
Medical Center, Department of Human and Clinical Genetics,
Wassenaarseweg 72, 2333 AL Leiden, The Netherlands.
E-mail: maarel@lumc.nl
816
© 2001 Wiley-Liss, Inc.
per arm and pelvic girdle muscles. Recently, attention
has been drawn to the absence of facial weakness and
pelvic girdle onset.1–3 Clinical uncertainties in some
patients and the high frequency of new mutations
make reliable DNA diagnosis mandatory for genetic
confirmation and counseling.
FSHD is associated with partial deletions of the
polymorphic D4Z4 repeat array on 4q35. This array is
visualized in EcoRI-digested DNA by hybridization
with probe p13E-11 (D4F104S1), which recognizes
the region proximal to the D4Z4 repeat (Fig 1). In
normal people, the array varies between 11 to 150
units; patients carry an allele of 1 to 10 units (10 to
38kb).4,5 DNA diagnosis is compromised by crosshybridization of p13E-11 to a highly homologous
polymorphic array on 10q26.6,7 At least 10% of chromosome 10-derived fragments in the population are
⬍38kb and do not cause disease. The restriction enzyme BlnI specifically recognizes chromosome 10derived units, but not chromosome 4-derived units.8
Therefore, BlnI-insensitive chromosome 4 alleles can
be discriminated from BlnI-sensitive chromosome 10
alleles by EcoRI/BlnI double digestion (Fig 2B; see Fig
1). Pulsed-field gel electrophoresis (PFGE), allowing
discrimination of fragments ⬎50kb and separation of
both 4 and 10 alleles, demonstrated the existence of
4-derived arrays on chromosome 10 or 10-derived arrays on chromosome 4.9 Hybrid repeat arrays consisting of mixtures of 4- and 10-derived units have also
been identified, adding to the complexity of the DNA
diagnosis. Especially in patients with a complex repeat
array composition, in patients in whom the probe region itself is also deleted, or in patients who display
somatic mosaicism for the repeat array deletion, PFGE
has proved very useful.9 –12
These complicated situations underscore the need
for simple and reliable tests without use of PFGE,
particularly when DNA testing is increasingly wanted
not only as a confirmatory but also as an exclusion
test.
Patients and Methods
Subjects
Control Subjects 1 and 2 are from a random Dutch population. Subject 3 is a de novo FSHD patient. Subject 4 is a
57-year-old man who was seen by his local neurologist for
shoulder pain. When he claimed that his cousin had FSHD,
DNA testing was performed showing a shortened EcoRI fragment, indicating that he a gene carrier with a probability of
greater than 98%. He was referred for a second opinion.
Apart from pain, he reported progressive difficulties raising
his arms above his head for a period of 10 years. The physical examination showed mild m. infraspinatus atrophy and
weakness (MRC grade 4), as well as bilateral deltoid, biceps,
and triceps weakness (grade 4). Painful elevation of the arms
limited to 145 degrees was present bilaterally. Exorotation of
ence of a novel consistent difference between both
units. A G-to-C transition (position 7515 in accession
no. AF117653) results in a single XapI restriction site
in the 4-derived unit. The 10-derived unit is completely resistant to XapI. Although XapI cuts the
D4F104S1 locus, resulting in weaker hybridization signals, probe p13E-11 is still applicable. A XapI restric-
Fig 1. Restriction map of the EcoRI fragments recognized by
p13E-11 (shaded) on chromosomes 4 (solid) and 10 (open)
based on one D4Z4 unit in sequence AF117653. Restriction
enzymes are EcoRI (E), BlnI (B) and XapI (X) and restriction sizes are in kilobases (kb). XapI cuts frequently around
the repeat array, therefore only relevant restriction fragments
are indicated.
the upper arms was restricted. He had no facial weakness or
other signs of FSHD. Creatine kinase was normal and an
extensive electromyelogram showed polyphasic potentials of
normal duration and amplitude in the left biceps muscle
only. Because the reduction of the EcoRI fragment after BlnI
digestion was greater than 3kb, additional genetic studies
were requested.
A cousin of Subject 4 was 65 years old and had a painful
right shoulder for many years. A minor stroke 2 years before
the examination had left the patient with a left-sided central
facial paresis and a restricted endorotation of the right arm.
The brother of this cousin was a 57-year-old left-handed
man with shoulder pain of 25 years duration. He had an
elevated left shoulder but no paresis or atrophy, and no signs
compatible with FSHD. Ten years earlier, an orthopedic surgeon had diagnosed his condition as bilateral rotator-cuff
syndrome. Electromyelography at that time was done because of bilateral supra- and infraspinatus atrophy, indicating
mild neurogenic and myopathic features, which his neurologist considered suggestive of FSHD.
Fig 2. (A) Pulsed-field gel electrophoresis (PFGE) analysis of
the repeat arrays on chromosomes 4 and 10 in the DNA of
control Subjects 1 and 2 after digestion with EcoRI/HindIII
(E), EcoRI/BlnI (B) or XapI (X) and hybridization with
probe p13E-11. In PFGE analyses, HindIII is added to the
EcoRI restriction since this enzyme increases the resolution
within the 20- to 50-kb range and does not cut within the
repeat array itself. Individual 1 carries a standard allele configuration of two 4-derived (BlnI-resistant) alleles of 65kb and
40kb, and two 10-derived (XapI-resistant) alleles of 100kb
and 50kb. Individual 2 carries co-migrating 4-derived and
10-derived alleles of 120kb based on the resistance to both
enzymes. (B) Schematic presentation of the D4Z4 locus (solid)
and its homologue on chromosome 10 (open). The repeat
units are represented by an arrow and may vary in number
(n). The region recognized by probe p13E-11 is shaded. The
restriction sites for EcoRI (E), BlnI (B) and XapI (X) are
indicated. Above the chromosome, the restriction fragments are
visualized by solid bars, after digestion with the proper enzymes for chromosome 4qter. Below the chromosome, the restriction fragments for 10qter are visualized. The allele sizes of
Subject 1 are indicated on the proper restriction fragments.
DNA Isolation
For linear gel electrophoresis, DNA was isolated from peripheral blood lymphocytes essentially as described.13 For
PFGE, peripheral blood lymphocytes were embedded in agarose plugs at a concentration of 7.5 ⫻ 105 cells per plug.
DNA Diagnosis
DNA digestion, separation by linear gel electrophoresis or
PFGE, Southern blotting, and hybridization were carried out
as described previously.9,14 XapI was purchased from Fermentas. Blots were exposed for 16 to 24 hours to phosphorimager screens and analyzed with the ImageQuant software
program (MBI Fermentas, St. Leon-Rot, Germany).
Results
Sequence comparison of eight (4-derived) D4Z4 units
and seven 10-derived units from GenBank and sequences generated in our laboratory showed the pres-
Lemmers et al: Genetic Diagnosis of FSHD
817
tion site distal to the repeat array obviates a double
digest (see Figs 1 and 2B).
We tested this difference in 50 healthy controls and
20 FSHD patients who had been examined previously
for their repeat array constitution. No inconsistencies
were identified; upon EcoRI/BlnI digestion, 4-derived
arrays were visualized, while upon XapI digestion, only
10-derived repeat arrays were seen. As demonstrated in
Figure 2A, XapI not only facilitates the proper assignment of each allele to its respective chromosome, as
exemplified in control 1, but also assists in the identification of equal-size 4-derived and 10-derived alleles,
as shown in control 2. This individual carries comigrating 4-derived and 10-derived alleles of 120kb, as
inferred from its resistance to BlnI and XapI.
Patients 3 and 4 (Fig 3A) were referred for the diagnosis of FSHD. Routine DNA diagnosis includes digestion of DNA with EcoRI and double digestion with
EcoRI/BlnI prior to separation by linear gel electrophoresis. As shown in Figure 3A, Patient 3 carries a
standard FSHD 4-derived allele of 17kb, based on its
BlnI resistance and XapI sensitivity, confirming the
clinical diagnosis of FSHD.
Patient 4 carries a 30-kb fragment upon digestion
with EcoRI, while EcoRI/BlnI double digestion shows a
fragment of 17kb, possibly derived from the 30-kb
EcoRI fragment. Based on these two enzymes, he was
previously considered gene carrier. XapI demonstrates
that the 30-kb EcoRI fragment is a homogeneous 10derived array and that, therefore, the 17-kb EcoRI/BlnI
fragment cannot be derived from the 30-kb EcoRI fragment. Further PFGE analysis (see Fig 3B) reveals the
original allele from which the 17-kb EcoRI/BlnI fragment is derived. It shows a 4-derived (BlnI-resistant)
allele of 90kb, two 10-derived (XapI-resistant) alleles of
80kb and 30kb, respectively, and a BlnI- and XapIsensitive allele of 250kb. Since the 90-, 80-, and 30-kb
fragments contain homogeneous arrays, the 17-kb
EcoRI/BlnI fragment has to come from the hybrid
250-kb allele, ruling out FSHD. Subsequent DNA
analysis of his cousins supported this interpretation because it provided no evidence for repeat array fragments of less than 38kb (data not shown).
Discussion
In recent years, unusual manifestations of FSHD have
gained considerable attention in the literature, emphasizing the need for a reliable genetic test for
FSHD.2,3,15–19 In a clinically highly selected population, we reached a sensitivity and specificity of the test
of more than 95%.14 This led to a liberal use of the
test for exclusion purposes, and to a potential rise in
the number of false-positive results.
The molecular diagnosis of FSHD is complicated by
the co-hybridizing homologous repeat array on chromosome 10qter, which may vary between 1 to 150
818
Annals of Neurology
Vol 50
No 6
December 2001
Fig 3. (A) Linear gel analysis of two potential facioscapulohumeral muscular dystrophy (FSHD) patients for genetic diagnosis of FSHD. Fragment sizes in the marker lane (M) are
indicated in the middle. The cross-hybridizing 9.4-kb chromosome Y fragment is indicated on the right. DNA of these individuals was digested with EcoRI (E), EcoRI/BlnI (B) and
with XapI (X) and separated in adjacent lanes. The new informative XapI fragment is indicated with an arrowhead.
Patient 3 carries a standard FSHD allele of 17kb. The fragment is resistant to BlnI digestion and becomes reduced to
14kb due to the BlnI site 3kb distal to the proximal EcoRI
site; therefore, it contains chromosome 4-derived repeats and is
sensitive to XapI digestion. In another hospital, Patient 4,
clinically diagnosed as possibly having FSHD, was originally
genetically diagnosed with FSHD with an hybrid allele of
30kb decreasing to 17kb after EcoRI/BlnI double digestion.
Further analysis with XapI showed that the 30-kb fragment is
a homogeneous 10-derived array, based on its XapI resistance.
Consequently, the 17-kb EcoRI/BlnI fragment cannot be derived from the 30-kb array. (B) Pulsed-field gel electrophoresis
(PFGE) analysis of Patient 5 carrying a potential hybrid repeat array of 30kb. Combinatory analysis with EcoRI/
HindIII, BlnI and XapI shows that the 250-kb allele is the
only allele that is sensitive to both discriminating enzymes.
The other three alleles are homogeneous arrays, since they are
resistant to BlnI or XapI. It is concluded that the 17-kb
EcoRI/BlnI hybrid fragment (arrowhead) is not derived from
the 30-kb allele, but rather from the 250-kb allele (arrow).
FSHD is therefore excluded in this patient. (C) Schematic
representation of the hybrid allele of Patient 4. Chromosome
4-derived units are solid, 10-derived units are open. The
restriction sites for EcoRI (E), BlnI (B) and XapI (X) are
indicated. Fragment sizes of the hybrid allele in Patient 4 are
indicated below the chromosome.
units without pathological consequences, and by the
presence of translocated or hybrid repeat arrays in some
21% of the Dutch population.9,11,20 In contrast to an
earlier report,9 recent improvements in genetic diagno-
sis showed that only homogeneous or hybrid 4-derived
arrays of less than 38kb on chromosome 4 have been
identified in FSHD. Short homogeneous 10-derived
arrays on chromosome 4 or, small repeat arrays on
chromosome 10, irrespective of their composition, have
never been associated with disease. Unfortunately, the
current techniques do not permit determination of the
original EcoRI fragment from which hybrid EcoRI/BlnI
fragments are derived.
Introduction of the restriction enzyme XapI refines
FSHD diagnosis. XapI has opposite characteristics to
BlnI: it recognizes a single restriction site within the
4-derived repeat unit, while the 10-derived repeat unit
is XapI-resistant. Therefore, digestion of DNA with
EcoRI, with EcoRI/BlnI, and with XapI, allows unequivocal determination of chromosome 4-derived and
10-derived alleles. XapI is particularly useful when repeat arrays are composed of clusters of 4-derived and
10-derived repeat units, in which it provides complete
allele information. Patient 4 (see Fig 3A–C) exemplifies
the power of this procedure, since a potential hybrid
short repeat array of four 4-derived repeat units (17kb),
followed by three 10-derived units (13kb) in a telomeric direction, would have explained the 30-kb EcoRI
fragment, in a clinically atypical FSHD patient. However, the XapI digest indicates that the 30-kb EcoRI
fragment is a homogeneous 10-derived repeat and that,
therefore, the 17-kb EcoRI/BlnI hybrid fragment cannot have been derived from the 30-kb EcoRI fragment.
Indeed, PFGE analysis demonstrates the presence of a
250-kb EcoRI fragment sensitive to BlnI and XapI from
which the 17-kb EcoRI/BlnI fragment must be derived.
This was supported by the finding that his supposedly
affected cousins did not carry alleles ⬍38kb. Since we
have not observed a small fragment with BlnI-sensitive
repeats, residing on chromosome 4 and responsible for
FSHD, there is no genetic support for the diagnosis of
FSHD.
Although such complicated allele constitutions are
probably rare, the increasing use of the DNA test as
exclusion criterion necessitates the additional use of
XapI to obtain complete allele information.
This work is funded by the Prinses Beatrix Fonds, the Dutch FSHD
Foundation, the Muscular Dystrophy Association (USA), the FSH
Society (USA), and the Association Française Contre les Myopathies.
S.M.vd.M. is a Gisela Thier Fellow of the Leiden University Medical Center.
References
1. Padberg GW. Facioscapulohumeral disease. Thesis. Leiden University, 1982.
2. Felice KJ, North WA, Moore SA, Mathews KD. FSH dystrophy 4q35 deletion in patients presenting with facial-sparing
scapular myopathy. Neurology 2000;54:1927–1931.
3. van der Kooi AJ, Visser MC, Rosenberg N, et al. Extension of
the clinical range of facioscapulohumeral dystrophy: report of
six cases. J Neurol Neurosurg Psychiatry 2000;69:114 –116.
4. Wijmenga C, Hewitt JE, Sandkuijl LA, et al. Chromosome 4q
DNA rearrangements associated with facioscapulohumeral muscular dystrophy. Nature Genet 1992;2:26 –30.
5. van Deutekom JC, Wijmenga C, van Tienhoven EA, et al.
FSHD associated DNA rearrangements are due to deletions of
integral copies of a 3.2 kb tandemly repeated unit. Hum Mol
Genet 1993;2:2037–2042.
6. Bakker E, Wijmenga C, Vossen RH, et al. The FSHD-linked
locus D4F104S1 (p13E-11) on 4q35 has a homologue on
10qter. Muscle Nerve 1995;2:S39 – 44.
7. Deidda G, Cacurri S, Grisanti P, et al. Physical mapping evidence for a duplicated region on chromosome 10qter showing
high homology with the facioscapulohumeral muscular dystrophy locus on chromosome 4qter. Eur J Hum Genet 1995;3:
155–167.
8. Deidda G, Cacurri S, Piazzo N, Felicetti L. Direct detection of
4q35 rearrangements implicated in facioscapulohumeral muscular dystrophy (FSHD). J Med Genet 1996;33:361–365.
9. van Deutekom JC, Bakker E, Lemmers RJ, et al. Evidence for
subtelomeric exchange of 3.3 kb tandemly repeated units between chromosomes 4q35 and 10q26: implications for genetic
counselling and etiology of FSHD1. Hum Mol Genet 1996;5:
1997–2003.
10. Cacurri S, Piazzo N, Deidda G, et al. Sequence homology between 4qter and 10qter loci facilitates the instability of subtelomeric KpnI repeat units implicated in facioscapulohumeral
muscular dystrophy. Am J Hum Genet 1998;63:181–190.
11. Lemmers RJLF, van der Maarel SM, van Deutekom JCT, et al.
Inter- and intrachromosomal subtelomeric rearrangements on
4q35: implications for facioscapulohumeral muscular dystrophy
(FSHD) aetiology and diagnosis. Hum Mol Genet 1998;7:
1207–1214.
12. van der Maarel SM, Deidda G, Lemmers RJ, et al. De novo
facioscapulohumeral muscular dystrophy: frequent somatic
mosaicism, sex-dependent phenotype, and the role of mitotic
transchromosomal repeat interaction between chromosomes 4
and 10. Am J Hum Genet 2000;66:26 –35.
13. Miller SA, Dykes DD, Polesky HF. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res 1988;16:1215.
14. Bakker E, van der Wielen MJ, Voorhoeve E, et al. Diagnostic,
predictive, and prenatal testing for facioscapulohumeral muscular dystrophy: diagnostic approach for sporadic and familial
cases. J Med Genet 1996;33:29 –35.
15. Brouwer OF, Padberg GW, Ruys CJ, et al. Hearing loss in
facioscapulohumeral muscular dystrophy. Neurology 1991;41:
1878 –1881.
16. Brouwer OF, Padberg GW, Bakker E, et al. Early onset facioscapulohumeral muscular dystrophy. Muscle Nerve 1995;2:
S67–S72.
17. Funakoshi M, Goto K, Arahata K. Epilepsy and mental retardation in a subset of early onset 4q35⫺ facioscapulohumeral
muscular dystrophy. Neurology 1998;50:1791–1794.
18. Miura K, Kumagai T, Matsumoto A, et al. Two cases of chromosome 4q35-linked early onset facioscapulohumeral muscular
dystrophy with mental retardation and epilepsy. Neuropediatrics 1998;29:239 –241.
19. Felice KJ, Moore SA. Unusual clinical presentations in patients
harboring the facioscapulohumeral dystrophy 4q35 deletion.
Muscle Nerve 2001;24:352–356.
20. van Overveld PG, Lemmers RJ, Deidda G, et al. Interchromosomal repeat array interactions between chromosomes 4 and 10:
a model for subtelomeric plasticity. Hum Mol Genet 2000;9:
2879 –2884.
Lemmers et al: Genetic Diagnosis of FSHD
819
So Near Yet So Far: Neglect
in Far or Near Space
Depends on Tool Use
Alan J. Pegna, PhD, Leila Petit, MA,
Anne-Sarah Caldara-Schnetzer, MA, Asaid Khateb, PhD,
Jean-Marie Annoni, MD, Roman Sztajzel, MD,
and Theodor Landis, MD
The study of unilateral spatial neglect has shown that
space can be dissociated on a peripersonal versus extrapersonal basis. We report a novel type of dissociation
based on tool use in a patient suffering from left neglect.
Line bisection was carried out in near and far space, using a stick and a laser pointer. A rightward bias was always found for the former, but not for the latter. Neglect
thus appears to be contingent not only on distance, but
also on the motor action required by the task.
Ann Neurol 2001;50:820 – 822
right parietal infarct. Our investigation witnessed yet another
pattern of results.
Case Report
Patient C.M. is a right-handed 87-year-old French-speaking
man who had longstanding hypertension. When a sudden
weakness in his left upper limb was noted, he was brought to
the hospital.
On admission, neurological examination indicated temporal disorientation, dysarthria with hypophonia, a left homonymous hemianopia, a left facial droop, and left hypesthesia.
He was completely hemiplegic on the left side and showed
diminished sensory functions for touch, pain, temperature,
and vibration on the left side. A left USN was noted. EchoDoppler of the cervical arteries showed a 40% stenosis of the
right internal carotid artery. A computed tomography scan of
the brain performed 24 hours after the onset of symptoms
showed an ancient infarct located in the right posterior
watershed region. Ten days later, a computed tomography
scan of the brain showed acute infarcts with contrast enhancement involving the right pre- and postrolandic regions, as
well as the posterior arm of the internal capsule.
Neuropsychological Assessment
Recent studies of patients suffering from unilateral spatial neglect (USN) have produced evidence suggesting that near
(peripersonal) and far (extrapersonal) space are not coded by
identical brain networks. Indeed, brain injury can affect either representation selectively. Halligan and Marshall1 first
reported a patient who exhibited USN in a line-bisection
task carried out within grasping space, but these investigators
failed to show any deviations when the lines were situated in
extrapersonal space and bisection carried out with a light
pen. Later evidence2–5 showed the opposite dissociation with
USN present in far space, but not near space.
Recently, Berti and Frassinetti6 reported that the limit between far and near space could be modulated through the
use of a tool. Indeed, their patient showed peripersonal, but
not extrapersonal, USN. Nevertheless, a rightward bias in
line bisection appeared when the stimuli were placed beyond
grasping distance, when the task was carried out with a stick.
These investigators concluded that the use of a stick produced an extension of body space resulting in a recoding of
“far” space as “near” by the relevant brain structures, consistent with suggestions from research in monkeys.7,8
Considering the importance of these findings, we sought
to investigate them further in a patient who showed left
USN restricted to peripersonal space after he sustained a
From the Neurology Clinic, Geneva University Hospitals, Geneva,
Switzerland.
Received Jun 21, 2001, and in revised form Sep 10, 2001. Accepted
for publication Sep 10, 2001.
Published online Nov 2, 2001; DOI: 10.1002/ana.10058
Address correspondence to Dr Pegna, Neurology Clinic, Geneva
University Hospitals, 24 Rue Micheli-du-Crest, 1211 Geneva 14,
Switzerland. E-mail: alan.pegna@hcuge.ch
820
© 2001 Wiley-Liss, Inc.
A comprehensive neuropsychological examination was carried out at 8 and 10 day after admission. On both days he
was cooperative and slow and presented attentional fluctuations. He complained spontaneously of hemiplegia and of
speech and memory disturbances. Speech was slurred, and
his voice was weak and monotone.
There was no aphasia. The patient displayed spatial dysgraphia when writing short sentences; he also omitted words
on the left side of the text when reading. Similarly, drawings
were incomplete in the left visual half-field. Line bisection
tested clinically showed a clear rightward bias, as well as the
omission of lines situated on the left side of the page. There
was no representational neglect. Visual recognition in the
right visual half-field was assessed clinically and did not show
any signs of visual agnosia. A number of motor perseverations were also noted on graphic productions. A mild memory impairment was noted on the Rey auditory–verbal learning task.
Method
The patient was tested on a controlled line-bisection task in
which the size of the lines and the distance from the stimuli
are systematically varied. Three male control subjects (aged
87, 86, and 80) hospitalized for non-central nervous system
diseases served as controls in the same line bisection task.
The patient and the control subjects gave informed consent
to participate in the test. The experiment was carried out
with the subjects comfortably seated in a quiet room.
The distances were selected such that three were within
grasping distance and three were in extrapersonal space. Line
bisection was thus carried out at 30, 55, 80, 110, 140, and
170cm from the patient’s eyes, with the first three distances
corresponding to near space and the latter three to far space.
The sizes of the lines presented were established to correspond to visual angles of 15, 30, and 45 degrees at each of
the six possible distances. Lines were drawn with black ink
Table. Determination of Extent to Which Deviations Should Be Considered Pathological
CM
Controls
Percentile limits (5th–95th)a
Reaching Near
Pointing Near
Reaching Far
Pointing Far
15.4 (14.3–17.5)
1.4
⫺1.6–4.2
2.3 (1.6–3.3)
0.5
⫺2.3–2.5
7.7 (1.4–8.0)
2.0
⫺1.1–3.5
0.8 (⫺6.2–4.3)
0.2
⫺2.1–1.4
Median displacement during line bisection in far and near space, using laser light pen (pointing) or pencil/stick (reaching) of patient C.M. (with
upper and lower quartiles given in parentheses) and controls. Values are percentage displacement errors (positive values indicate a rightward
displacement).
a
Obtained from controls.
on white paper and were placed on a cardboard for testing.
The lines were positioned at eye level, with the center of
each line corresponding to the midline.
The complete set of lines was bisected first using a pencil
(attached to a 150cm pole for distances of ⬎80cm), and
then again using a projection light pen that was placed in the
right hand and held close to the sternum. Thirty-six measures were thus obtained for every subject (3 line sizes ⫻ 6
distances ⫻ 2 bisection conditions).
The deviations from the center produced by the subjects,
measured in degrees of visual angle, were then transformed
into percentages with respect to the size of the lines. A value
of 0 indicated that the bisection was situated correctly in the
center. Deviation of the subject’s response to the right of the
objective center (corresponding to left neglect) was indicated
by a positive value. Deviations to the left were indicated by
negative values.
Results
For the patient, the median percentage displacement
from the center, along with the upper and lower quartile range, are shown in the Table for each of the 2 ⫻
2 conditions: near space versus far space and pointing
(light pen) versus reaching (pencil and pole). The differences between conditions are statistically significant,
as determined by Kruskal-Wallis one-way analysis of
variance by ranks test [H(3) ⫽ 19.3; N ⫽ 36; p ⫽
0.0002]. As is obvious from the data, deviations are
greatest for near space in the reaching condition, followed by bisection in extrapersonal space with a stick.
By contrast, line bisection in near and far space with a
light pen shows only a minimal deviation.
To determine the extent to which the deviations
should be considered pathological, the values obtained
from the controls were used to compute the 5th to
95th percentile limits (values generally used as a
boundaries for “normal” function in neuropsychological testing) in each of the four conditions (see Table).
The Figure presents the patient’s results plotted
along with the normal limits produced by controls.
The deviation in near space with a pencil is pathological. Although less pronounced, a similar statement can
be made when bisection is carried out in extrapersonal
space by means of a pole. When using a light pen,
however, the patient does not produce any signs of neglect, whether in near or in far space.
Discussion
The key finding in this study was that USN was not
observed when the patient bisected the lines with a light
projection pen whether the task was carried out in near
or in far space. By contrast, the use of the pencil and
stick produced a rightward bias, whatever the distance.
One possible explanation is that the representation
of space may be modified depending on the action to
be carried out. In other words, the representation of far
or near space could be influenced by the motor response required when measuring neglect. This hypothesis has been repeatedly addressed in the literature. To
circumvent motor responses, for example, USN has
been evaluated in near and far space, using optical illusions though no dissociation was observed between
distances.9 However, dissociations could result from
the effect of lesions on motor programs, rather than on
a more perceptual level of neglect.3,7
Proof of a differential effect of response mode on the
intensity of USN comes from a number of earlier reports. For example, USN has been found to be less
marked in a detection task using visuospatial stimuli
than verbal.10 Furthermore, neglect patients show a
greater number of errors in a pointing task when using
the right hand, rather than the left hand,11 suggesting
that some interaction takes place between the motor
act and the processing of information. Finally, a patient has been reported in whom perceptual tasks (eg,
reading) were less markedly impaired than when a motor component was present (eg, line bisection).5
These observations, along with our data, suggest that
during the course of information processing, the action
required by the task determines which representation
of space should be activated.
Interestingly, when using a stick, USN in far space is
less pronounced than in near space. Similarly, the use
of a light pen shows a slightly greater rightward shift in
near than far space. Thus, an explanation given strictly
in terms of the “action” hypothesis would also appear
insufficient. Rather, our findings demonstrate that not
only is USN dissociable in terms of far and near space,
but also what is considered to be near or far by the
brain is at least partially determined by the type of action required with respect to the object. These findings
Pegna et al: Tool-Dependent Hemineglect
821
Fig. Percentage deviation of patient C.M. (—䊐—) in near (A) and far (B) space, using a pencil/stick (reaching condition) or a
light pen (pointing condition). Positive values indicate a rightward displacement. Dashed lines represent 5 to 95 percentile limits
produced by controls.
point to a need to test USN while varying the motor
involvements of the tasks, as has recently been suggested.3
This research was supported by the Swiss National Science Foundation (3100-056782.99).
References
1. Halligan PW, Marshall JC. Left neglect for near but not far
space in man. Nature 1991;350:498 –500.
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3. Cowey A, Small M, Ellis S. No abrupt change in visual hemineglect from near to far space. Neuropsychologia 1999;37:1– 6.
4. Barrett AM, Schwartz RL, Crucian GP, et al. Attentional grasp
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5. Vuilleumier P, Valenza N, Mayer E, et al. Near and far visual
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6. Berti A, Frassinetti F. When far becomes near: remapping of
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7. Iriki A, Tanaka M, Iwamura Y. Coding of modified body
schema during tool use by macaque postcentral neurones. Neuroreport 1996;7:2325–2330.
8. Colby CL. Action-oriented spatial reference frames in cortex.
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