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Cytochrome c Oxidase subunit I microdeletion in a patient with motor neuron disease.

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could affect the structure of the transmembrane domain of the CLN3 protein or interfere with its incorporation into the membrane, in either case putatively
affecting its function.
Note Added in Proof
Since the acceptance of this article, 22 different mutations in CLN3 gene, apart from the common deletion,
have been discovered.20
This study was supported in part by the New York State Ofice of
Mental Retardation and Developmental Disabilities; the Batten’s
Disease Support and Research Association, Lance W. Johnston, Executive Director; and the Children’s Brain Disease Foundation, Dr
Alfred J. Rider, President.
We thank M. Stoddard-Marlow for copyediting the manuscript and
Lawrence Black for bibliographical assistance.
References
1. Zeman W. The neutonal ceroid-lipofuscinoses. Prog Neuropath01 1976;3:203-223
2. Berkovic SF, Carpenter S, Andermann F, et al. Kufs’ disease: a
critical reappraisal. Brain 1988;111:27-62
3. Wisniewski KE, Rapin I, Heaney-Kieras J. Clinico-pathological
variability in the childhood neuronal ceroid-lipofuscinoses and
new observations on glycoprotein abnormalities. Am J Med
Genet 1988;(suppl 5):27-46
4. Batten FE. Cerebral degeneration with symmetrical changes in
the maculae in two members of a family. Trans Ophthalmol
SOCUK 1903;23:386-390
5. The International Batten Disease Consortium. Isolation of a
novel gene underlying Batten disease, CLN3. The International
Batten Disease Consortium. Cell 1995;82:949-957
6. Mitchison HM, Munroe PB, O’Rawe AM, et al. Genomic
structure and complete nucleotide sequence of the Batten disease gene, CLN3. Genomics 1997;40:346-350
7. Munroe PB, O’Rawe AM, Mitchison HM, et al. Spectrum and
functional consequences of mutations in CLN3. Sixth International Congress on Neuronal Ceroid-Lipofuscinoses (NCL-96),
June 8-11, 1996, Gustavelund, Finland; final program and abstracts, p 18 (Abstract)
8. Janes RW, Munroe PB, Mitchison HM, et al. A model for
Batten disease protein CLN3: functional implications from homology and mutations. FEBS Lett 1996;399:75-77
9. Goebel HH, Gullotta F, Bajanowski T, et al. Pigment variant
of neuronal ceroid-lipofuscinosis. Am J Med Genet 1995;57:
155-159
10. Carpenter S , Karpati G, Wolfe LS, Andermann F. A type of
juvenile cerebromacular degeneration characterized by granular
osmiophilic deposits. J Neurol Sci 1973; 18:67-87
11. Ebhardt G, Cervus-Navarro J, Burgel P. Klinische und ultrastrukturella Befunde bei einer juvenilen Form der amaurtoischem Idiotie mit protrahiertem Verlauf. Arch Psychiatr Nervenkr 1973;218:79-91
12. Goebel HH, Pilz H, Gullotta F. The protracted form of juvenile neuronal ceroid-lipofuscinosis. Acta Neuropathol (Berl)
1976;36:393-396
13. Kohlschiitter A, Laabs R, Albani M. Juvenile neuronal ceroid
lipofuscinosis (JNCL): quantitative description of its clinical
variability. Acta Paediatr Scand 1988;77:867-872
14. Zhong N, Wisniewski KE, Kaczmarski AL, et al. Molecular
screening of Batten disease: identification of a missense mutation (E295K) in the CLN3 gene. Hum Genet (In press)
110
Copyright
0 1918 by
15. Bardeesy N, Pelletier J. Mutational detection by single-strand
conformational polymorphism. Methods Neurosci 1995;26:
163-1 83
16. Wisniewski KE, Kida E, Patxot OF, Connell F. Variability in
the clinical and pathological findings in the neuronal ceroid
lipofuscinosis: review of data and observations. Am J Med
Genet 1992;42:525-532
17. Goebel HH. Protracted juvenife neuronal ceroid-lipofuscinosis.
J Inherit Metab Dis 1993;16:233-236
18. Mitchison HM, O’Rawe AM, Lerner TJ, et al. Refined localization of the Batten disease gene (CLN3) by haplotype and
linkage disequilibrium mapping to DlGS288-DlGS383 and
exclusion from this region of a variant form of Batten disease
with granular osmiophilic deposits. Am J Med Genet 1995;57:
3 12-3 15
19. Piberg L, Jarvela I, Autti T, et al. A Finnish JNCL patient homozygous for the major 1.02 kb deletion of the CLN3 gene
with granular osmiophilic deposits (GRODs). Sixth International Conference on Neuronal Ceroid-Lipofuscinoses (NCL96), June 8-1 1, 1996, Gustavelund, Finland; final program
and abstracts, p 111 (Abstract)
20. Munroe PB, Mitchison HM, O’Rawe AM, et al. Spectrum of
mutations in the Batten disease gene, CLN3. Am J Hum Genet
1997;61:310-316
Cytochrome c Oxidase
Subunit I Microdeletion
in a Patient with Motor
Neuron Disease
Giacomo P. Comi, M D , * Andreina Bordoni, BS,*
Sabrina Salani, BS,* Liliana Franceschina, BS,*
Monica Sciacco, MD,* Alessandro Prelle, M D , *
Francesco Fortunato, BS,* Massimo Zeviani, MD, PhD,t
Laura Napoli, BS,* Nereo Bresolin, M D , *
Maurizio Moggio, MD,* Carlo D. Ausenda, MD,*
Jan-Willem Taanman, MD,+
and Guglielmo Scarlato, M D *
~
An out-of-frame mutation of the mitochondrial DNAencoded subunit I of cytochrome c oxidase (COX) was
discovered during investigation of a severe isolated muscle COX deficiency in a patient with motor neuron-like
degeneratioq. The mutation is a heteroplasmic 5-bp
microdeletion located in the 5’ end of the COI gene,
_____
From *Centre Din0 Ferrari, Istituto di Clinica Neurologica, Universita’ degli Studi di Milano, IRCCS Ospedale Maggiore Policlinico, Milan, and TOspedale Bambin Gesu’, Rome; Istituto Nazionale Neurologico “C. Besta,” Department of Biochemistry and
Genetics, Milan, Italy; and $Academic Medical Center, Amsterdam,
The Netherlands.
Received Mar 31, 1997, and in revised form Sep 5. Accepted for
publication Sep 5, 1997.
Address correspondence to Dr Comi, Istituto di Clinica Neurologica, Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122
Milan, Italy.
the American Neurological Association
leading to premature termination of the corresponding
translation product. Western blot analysis, immunohistochemistry, and single-fiber polymerase chain m&rr
demonstrated a tight correlation between COX defect,
COX I expression, and percentage of mutation. COX
subunits 11, 111, and N were decreased as well, suggesting
a defective assembly of COX holoenzyme. The mutation
was associated with a clinical phenotype unusual for a
mitochondrial disorder, that is, an isolated motor neuron
disease (MND) with some atypical findings, including
early onset, preferential involvement of the upper motor
neuron, and increased cerebrospinal fluid protein content. MND may arise from impaired scavenging and
overproduction of free oxygen radicals, a by-product of
oxidative phosphorylation (OXPHOS). Our observation
suggests that OXPHOS impairment could play a role in
the pathogenesis of some MND cases.
Comi GP, Bordoni A, Salani S, Franceschina L,
Sciacco M, Prelle A, Fortunato F, Zeviani M,
Napoli L, Bresolin N, Moggio M, Ausenda CD,
Taanman J-W, Scarlato G. Cytochrome c oxidase
subunit I microdeletion in a patient with motor
neuron disease. Ann Neurol 1998;43:110-116
Human cytochrome c oxidase (COX), the terminal
component of the mitochondrial respiratory chain,
transfers electrons from reduced cytochrome c to molecular oxygen. COX is a multiheteromeric enzyme
composed of 13 protein subunits.’ T h e three largest
(COX I, COX 11, and COX 111) are encoded by mitochondrial DNA (mtDNA).
Mutations of m t D N A affecting mitochondrial translation, such as point mutations in tRNA-encoding
genes or large-scale rearrangements, can be associated
with COX deficiency, usually combined with defects in
other mtDNA-related complexes.’ Despite the common occurrence of COX deficiency as cause of oxidative phosphorylation (OXPHOS) defects, only one
mutation has been reported in a COX-encoding gene,
namely, a heteroplasmic, 15-bp, in-frame microdeletion in the COIII gene, leading to a mild myopathy
with myoglobinuria in a single patienta3 Here we describe a new out-of-frame microdeletion affecting
the COI gene in a patient with an unusual clinical
phenotype-early-onset,
rapidly progressive motor
neuron disease (MND).
somatosensory evoked potentials were normal. Motor evoked
potentials showed increased latency and reduced amplitude
frr upper zrtd bwer iih k
&.
Brain magnetic czsmzmc
imaging (MRI) showed a bilateral lesion of the corticobulhar
tract. No other lesions of the central nervous system (CNS)
were detected (Fig 1). Cerebrospinal fluid (CSF) protein
content was 57 mg/dl (n.v., 15-50 mg/dl), without oligoclonal bands. GM1, GDla, and MAG (myelin-associated
glycoprotein) antibodies were negative. The electrocardiogram was normal. At 33 years of age, he showed a spastic
tetraparesis, with mild dysphagia and dysarthria with active
pharyngeal reflex. Rare fasciculations were present in the upper and lower limbs. The level of serum lactate at rest was
23.4 mg/dl (n.v., 5.7-22 mg/dl). CSF protein level was 80.5
mg/dl. After informed consent, the patient underwent two
muscle biopsies, at 32 and 33 years of age, respectively. Biochemical and morphological analyses were performed on the
second biopsy, and mtDNA was analyzed in both. At age 34,
the worsening of bulbar signs led to pulmonary infection and
death. No autopsy was performed.
The patient’s mother and 3 sisters (including 2 monozygous twins) were healthy at 63, and 36 and 32, years of age,
respectively. The EMG was normal in all 4 subjects. No
morphological or biochemical abnormalities were found in
their muscle biopsies. Five years of follow-up failed to show
any change in their clinical condition.
Molphological, Histochemical, and
Biochemical Investigations
Histochemical reactions were performed on muscle biopsy by
following standard procedures.* Respiratory chain enzyme
activities were measured on muscle homogenate as deFor immunoblot analysis, muscle mitochondrial
fractions, at 30 kg/lane, were electrophoresed through 11%
or 12.5% sodium dodecyl sulfate (SDS)-polyacrylamidegels,
to visualize COX subunits I and 11, and I1 through IV, respectively. A 20% SDS-polyacrylamide gel was used to
screen COX I immunoreactivity in the low molecular weight
range. Gels were electroblotted onto a nitrocellullose filter at
75 V for 2 hours. The following primary antibodies were
used: mouse monoclonal antibody against human COX I naFig 1. T2-weighted magnetic resonance images showing focal
and symmetrical areas of increased white matter signal intensity from the parietal cortex to the cerebral peduncle.
Patient and Methods
Clinical Data
Our patient, a man, suffered from a progressive spastic paraparesis beginning at 29 years of age. At onset, lower motor
neuron signs were absent. After 1 year, upper motor neuron
signs spread to the upper limbs. At 32 years of age, the electromyelogram (EMG) showed high polyphasic motor unit
potentials; spontaneous activity was restricted to the first interosseus and tibialis anterior muscles. Auditory, visual, and
Brief Communication: Comi et al: COX I Microdeletion
111
tive protein (dilution 1:400), rabbit polyclonal antibody
against a COX I1 synthetic peptide encompassing amino acids 1 through 17 of the N-terminus (dilution 1:300), mouse
monoclonal antibody against yeast COX subunit I11 (dilution 1:150) (Molecular Probes, Leiden, The Netherlands),
and mouse monoclonal antibody against the bovine COX
subunit IV (dilution 1: 1,500) (Molecular Probes).
Diaminobenzidine-based immunostaining was performed,
using suitable horseradish peroxidase-conjugated secondary
antibodies (Dako, Copenhagen, Denmark). Immunohistochemistry against cox subunit I, 111, and IV was performed
as described.*
Table. Respiratory C h i n Enzyme Activities in
Muscle Homogenate
Cytochrome c oxidase
NADH dehydrogenase
Succinate dehydrogenase
N A D H - ~ reductase
~~
Succinate-cyt reductase
Patient
Controls (n = 43)
0.170
3.812
0.085
0,376
0.146
0.394 Ifr 0.071
3.227 ? 0.642
0.096 2 0.020
0.40 1 2 0.088
0.145 i 0.021
Values are normalized to the citrate synthase activity.
cyt
=
cyrochrome.
Genetic Analysis
Southern blot analysis of muscle mtDNA was performed according to described methods.’ A systematic mutation
screening in the 22 aRNA-encoding and the three COXencoding mt*NA genes Was Performed by heteroduplex
analysis of polymerase chain reaction (PCR)-amplified frag.ments.lU
The PCR fragment from nucleotide position 5,941
through 6,101, containing the mutation, was subcloned into
a suitable plasmid and sequenced by using a dye terminator
cycle sequencing kit (Perkin-Elmer, Foster City, CA) in an
Applied Biosystems 373A automated sequencer.
Fragment-length polymorphism (FLP) analysis was used
to verify the presence and the amount of the mutation. A
Tag I digestion restriction site is present at nucleotide position 6,014. A DNA band derived from the digestion with
Tag I of the PCR fragment encompassing nucleotide position 5,941 through 6,101 was used to detect the FLP produced by the 5-bp deletion.
Muscle sections stained consecutively by COX and succinate dehydrogenase (SDH) were subjected to single-fiber microdissection, PCR amplification, and FLP analysis as described.”
The coppertzinc superoxide dismutase (SODl) gene was
analyzed according to described methods.12
Results
COX histochemistry showed a large predominance of
negative and deficient fibers; about 13% of fibers were
stained intensely by SDH and appeared as ragged red
fibers ( W s ) by the trichrome Gomori modified stain.
Some hypotrophic angulated fibers belonging to both
type 1 and type 2 were also present. An isolated COX
deficiency (43.2% of control values) was demonstrated
by biochemical analysis of the respiratory chain (Table).
Immunohistochernistry showed a pronounced decrease of COX I-specific signal and a milder decrease
of COX I11 and IV immunoreactivity (Fig 2). The
densitometric integrated area of the immunoblot band
corresponding to COX I was 35% of control values,
whereas the signals specific to COX 11, COX 111, and
COX IV were 58940, 78%, and 65%, respectively (Fig
3). Immunoblot analysis with COX I antibody failed
to show any signal in the low molecular weight range
(2.5-20 kd).
Heteroduplex analysis of the PCR product corre-
112 Annals of Neurology Vol 43
No 1 January 1998
sponding to the mtDNA region from 5,941 through
6,101 showed a heteroplasmic pattern. This pattern
was absent in 80 ‘‘control’’muscle mrDNA samples belonging to 20 individuals with normal muscle biopsies
and 60 SubiectSwith mitochondrial disorders.
Sequence analysis demonstrated the presence of a
5-bp deletion that eliminates one of two 5-bp adjacent
repeated sequences encompassing nucleotide position
6,015 through 6,024 in the 5’ first portion of COI
(Fig 4A). A stop codon is created six codons downstream to the deletion, resulting in a very short predicted product (42-amino acid residues vs 5 13-amino
acid residues of the wild-type sequence).
The relative proportions of mutant versus wild-rype
mtDNA in the two muscle biopsies of the patient were
47% and 68.7%, respectively. No mutation was detected in the muscle biopsies of the patient’s relatives
(see Fig 4B).
Single-fiber PCR showed a strict correlation between
percentage of mutation and histochemical phenotypes
as follows: 28 2 8.5% in normal fibers (n = 18),
37.7 ? 11.2% in COX-deficient fibers (n = 11),
69 t 9.2% in COX-negative fibers (n = 15), and
91 2 14.4% in RRFs (n = 7) (see Fig 4C).
The SODl gene sequence was normal.
Discussion
The relevance of this study is twofold. From a molecular point of view, this is the first out-of-frame mutation in a COX subunit gene ever described. Muscle
biopsy analysis was consistent with a severe mitochondrial impairment; that is, pronounced COX deficiency
was present in most of the fibers, some of which appeared as W s . Similar features are observed in patients with large-scale rearrangements of mtDNA o r
point mutations of tRNA genes. However, in contrast
with the latter cases, biochemical analysis showed a
specific COX deficiency with preservation of the activities of the other respiratory chain enzymes. A 5-bp
microdeletion was found in the 5’ region of the COI
gene. The deletion abolishes one of two adjacent
CGAGC sequences, suggesting a mechanism of slippage and mispairing during mtDNA replication. This
Fig 2. Histochemical and immunohistochemical analysis of muscle biopsy sections (X 250). (a) Succinate dehydrogenase showing
three jbers with abnormal mitochondrial accumulation. (b) Cytocbrome c oxidax (COX) showing a pronounced deficiency in most
$beys; j w angulatedjbers are obsewed. (c and d) COX I imrnunostain showing a nearly complete lack of signal in patient? tissue
(c) and a normal mitochondrial stain in control tissue (d). (e) Patient? COX III immunostain showing a normal cytoplasmic pattern. (fi Patient? COX IV immunostain showing a normal cytoplasmic pattern.
is similar to what has been proposed for large mtDNA
deletions” as well as for a 15-bp COIII microdeletion.’ The 5-bp COI microdeletion fulfills the standard criteria for a pathogenic mtDNA mutation, as follows. First, the mutation was heteroplasmic, suggesting
that the potentially lethal effects of a mutation, causing
the destruction of an essential component of COX,
were partially mitigated by the coexistence of a substantial amount of wild-type mtDNA. Second, the mutation was absent in muscle mtDNA from many control subjects, indicating a segregation of the mutation
with the disease. Third, we found a strict correlation
between proportion of mutation, amount of COX I
protein, and severity of the biochemical defect. Fourth,
Brief Communication: Comi et
al:
COX I Microdeletion
113
Fig 3. Western blot analysis of muscle homogenate supernatant. (A) Cytochrome c oxidase (COX) I immunoblot. Lane 1 = human
purijed COX; lanes 2 and 4 = control muscles; lane 3 = patient; muscle. (B) COX 11 immunoblot. Lanes 1 and 3 = control
muscLes; lane 2 = patient? muscle; lane 4 = human pur;fed COX. (C) COX I11 immunoblot. Samples are loaded in the same
order as in A. (0) COX TV immunoblot. Samples are loaded in the same order as in B.
the distribution of the mutation in individual muscle
fibers correlates with their histochemical phenotype.
The frameshift produced by the mutation results in
a predicted truncated COX I peptide containing only
the NH, domain. The absence of COX I cross-reacting
material in the low molecular weight range supports
the hypothesis that the truncated peptide is rapidly degraded. However, it is possible that the NH, epitope is
not recognized by our antibody, which was raised
against the entire COX I native peptide. COX I is
thought to act as a transmernbrane “scaffold” for the
other subunits of COX.’ Accordingly, our immunohistochemical and immunoblot results showed a decreased
immunoreactivity not only of COX subunit I, but also
of subunits 11, 111, and IV, suggesting impaired assembly or increased instability of the holoenzyme.
114 Annals of Neurology Vol 43 No 1 January 1998
From a clinical point of view, the mutation was associated with an unusual presentation for mitochondrial disorders (ie, an MND-like phenotype). CNS involvement is known to be a cardinal feature of many
mitochondria1 disorders, but the pathogenesis of the
neuronal loss, and the regional distribution of specific
cases, are not well understood.‘* In our patient, the
neuronal degeneration could be the consequence of the
energy crisis due to the specific defect of COX. However, additional mechanisms can be proposed, including a toxic role of the truncated COX I peptide,15 or
the generation of free radicals due to impaired respirati~n.’~,’’The generation of reactive oxygen species is
known to play a key role in lymphocyte’* and neurorial" programmed cell death. Mutations of the SOD1
gene lead to familial amyotrophic lateral sclerosis, pos-
A
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Taql
L
L
I
R
A
C
L
G
G
P
G
N
L
L
G
N
CTC CTT ATT CGA GCC GAG CTG GGC CAG CCA GGC AAC CTT CTA GGT AAC
6015
6024
b
Taql
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CTC CTT ATT CGA GCI GGG CCA GCC AGG CAA CCT TCT AGG TAA
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sibly via the “gain” of a peroxidase function by the abnormal enzyme.20 Likewise, it is possible that overproduction of free radicals by genetically damaged
mitochondria can lead to a motor neuron-like disease
in selected cases.
Our patient presented with an early-onset and rapidly progressive MND with predominant signs of upper motor neuron system degeneration. MRI examination confirmed the specific involvement of the
corticospinal tract,21 whereas the rest of brain was
spared, including areas that are affected frequently in
mitochondrial diseases, such as the cerebral cortex, the
cerebellum, and the basal ganglia. The molecular features of the mutation and the severity of its functional
consequences on COX activity support the existence of
a pathogenetic link between mutation and phenotype.
However, the influence on the clinical presentation, of
additional factors including mutations in other nuclear
or mitochondrial genes, cannot be ruled out and requires further studies.
COX investigation should be performed in patients
Fig 4. (A) Scheme of COI gene in
control and patient mtDNA, showing, underlined, the 5-bp repeated
sequence (nucleotide position 6,0156024), as well as the Taq I restriction site at nucleotide position 6,014.
(B) Ethidium bromide-stained gel of
polymerase chain reaction of muscle
mtDNA fiom nucleotide position
5,941 through 6,101, fallowed by
Taq I digestion. The sizes of digested
products are given in base pairs (bp).
WiU-type mtDNA i s cut into two
fragments of 8 7 and 73 bp. The
presence of deleted mtDNA is indicated by an additionalfrapent of
82 bp. Lane I = control muscle
mtDNA; lane 2 = patient? muscle
mtDNA derived from the first muscle
biop9; lane 3 = patient, second
muscle biopsy; lanes 4, 5, and 6 =
muscle rntDNA from the patient? 3
sisters; lane 7 = muscle mtDNA
fFom the patient? mother. (C) Fragment-length polymorphism analyses
of individual microdissected fibers
derived fiom the patient? muscle
(lanes 1-7). Lanes 1 and 2 =
raaed red fibers; lanes 3 and 4 =
cytochrome c oxiduse (COX)-negative
fibers; lanes 5 and 6 = COXdeficient fibers; lane 7 = COXpositive fiber; lane 8 = COX-normal
control fiber.
with MND, especially if associated with atypical findings such as early onset, preferential upper motor neuron involvement, and increased CSF protein content.
This study was supported by a grant from IRCCS Ospedale Maggiore Policlinico, Milan, Italy (R.F. 1994), by Telethon Foundation
(grant 767 to M.Z.), and by the Associazione Amici del Centro
Din0 Ferrari.
Style revision by Barbara Zeviani is gratefully acknowledged.
References
1. Capaldi RA. Structure and function of cytochrome c oxidase.
Annu Rev Biochem 1990;59:569-596
2. Morgan-Hughes JA. Mitochondrial diseases. In: Engel AG,
Franzini-Amstrong C, eds. Myology. 2nd ed. New York:
McGraw-Hill, 1996: 1610-1660
3. Keightley JA, Hoffbuhr KC, Burton MD, et al. A microdeletion in cytochrome c oxidase (COX) subunit 111 associated with
COX deficiency and recurrent myoglobinuria. Nat Genet 1996;
12:410-416
4. Dubowitz V. Muscle biopsy: a practical approach. 2nd ed.
London: Bailliere Tindall, 1985
Brief Communication: Comi et al: COX I Microdeletion
115
5. Sottocasa GL, Kuylenstierna B, Ernster L, Bergstrand A. An
electron transfer system associated with the outer membrane of
the mitochondria. J Cell Biol 1969;32:415-438
6. King TE, Howard 13I. Preparation of succinate dehydrogenase
and reconstitution of succinate oxidase. Methods Enzymol
1969; 10:322-331
7. Srere PA. Citrate synthase. Methods Enzymol 1969;13:3-11
8. Tritschler H-J, Andteetta F, Moraes CT, et al. Mitochondrial
myopathy of childhood associated with depletion of mitochondrial DNA. Neurology 1992;42:209-217
9. Zeviani M, Bresolin N, Gellera C, et al. Nucleus-driven multiple large-scale deletions of the human mitochondrial genome:
a new autosomal dominant disease. Am J Hum Genet 1990;
47:904-914
10. Moraes CT, Ciacci F, Bonilla E, et al. Two novel pathogenetic
mitochondrial DNA mutations affecting organelle number and
protein synthesis. Is the tRNALe"'uuR) gene an etiologic hot
spot? J Clin Invest 1933;92:2906-2915
11. Moraes CT, Ricci E, Bonilla E, et al. The mitochondrial
tRNALeu(UUR)
mutation in MELAS: genetic, biochemical, and
morphological correlations in skeletal muscle. Am J Hum
Genet 1992;50:934-949
12. Yulug IG, Katsanis N, de Belleroche J, et al. An improved protocol for the analysis of SOD1 gene mutations, and a new mutation in exon 4. Hum Mol Genet 1995;4:1101-1104
13. Schon EA, Rizzuto R, Moraes CT, et al. A direct repeat is a
hotspot for large-scale deletion of human mitochondria1 DNA.
Science 1989;244:346-349
14. Cortopassi G, Wang E. Modelling the effects of age-related
mtDNA mutation accumulation: complex I, superoxide and
cell death. Biochem Biophys Acta 1995;1271:171-176
15. Morse M-C, Bleau G, Dabhi VM, et al. The COI mitochondrial gene encodes a minor histocompatibility antigen presented
by H2M3. J Immunol 1996;156:3301-3307
16. Pitkanen S, Robinson BH. Mitochondrial complex I deficiency
leads to increased production of superoxide radicals and induction of superoxide dismutase. J Clin Invest 1996;98:345-35 1
17. Mitsui T, Kawai H, Nagasawa M, et al. Oxidative damage to
skeletal muscle DNA from patients with mitochondrial encephalomyopathies. J Neurol Sci 1996;139:111-116
18. Zamzami N, Marchetti P, Castedo M, et al. Sequential reduction of mitochondrial transmembrane potential and generation
of reactivive oxygen species in early programmed cell death. J
Exp Med 1995;182:367-377
19. Greenlund LJS, Deckwerth TL, Johnson EM. Superoxide dismutase delays neuronal apoptosis: a role of reactive oxygen species in programmed neuronal death. Neuron 1995;14:303-315
20. Wiedau-Pazos M, Goto JJ, Rabizadeh S, et al. Altered reactivity
of superoxide dismutase in familial amyotrophic lateral sclerosis.
Science 1996;271:515-518
21. Goodin DS, Rowley HA, Olney RK. Magnetic resonance imaging in amyotrophic lateral sclerosis. Ann Neurol 1988;23:
418-420
Increased Serum Levels of
Soluble CD95 (APO-l/Fas)
in Relapsing-Remitting
Multiple Sclerosis
Frauke Zipp, MD,* Michael Weller, MD,*
Peter A. Calabresi, MD,? Joseph A. Frank, MD,t
Craig N. Bash, M D , t Johanna Dichgans, MD,*
Henry F. McFarland, MD,? and Roland Martin, MD*t
CD95/CD95 ligand interactions are critically involved in
the negative regulation of peripheral T-cell responses.
Here, we report that serum levels of soluble CD95 are
significantly elevated in patients with relapsing remitting
multiple sclerosis. In a transectional study, CD95 levels
did not correlate with clinical disability or lesion formation on magnetic resonance imaging. Longitudinally, Expanded Disability Status Scale changes were associated
with high CD95 levels. Interferon-@(IFNP) treatment
led to an initial increase and subsequent decline of serum
CD95 levels. Interestingly, patients generating neutralizing antibodies to the drug had significantly higher baseline CD95 levels before IFNP treatment than those without neutralizing antibodies.
Zipp F, Weller M, Calabresi PA, Frank JA,
Bash CN, Dichgans J, McFarland HF, Martin R.
Increased serum levels of soluble CD95 (APO-1/
Fas) in relapsing-remitting multiple sclerosis.
Ann Neurol 1998;43:116-120
Multiple sclerosis (MS) is considered a T-cell-mediated
autoimmune disease.' The presence of autoreactive T
cells in the normal immune repertoire suggests that
there are potent negative regulatory mechanisms for
the control of T-cell activity. The capability of autoreactive T cells to induce disease may be genetically controlled because, for example, T cells from HLA-DR2positive individuals produce higher amounts of tumor
necrosis factor (TNF) than T cells from DR2-negative
individuals.' Subtle signs of general immune dysregulation such as shifts in T-cell populations might be responsible for the induction of disease.334 However,
there may also be a defect in eliminating previously
activated T cells. The survival of activated T cells is
From the *Department of Neurology, University of Tubingen, Tubingen, Germany; and tNeuroimmunology Branch, NINDS, National Institutes of Health, Bethesda, MD.
Received May 1, 1997, and in revised form Sep 3. Accepted for
publication Sep 5, 1997.
Address correspondence to Dr Zipp, Department of Neurology,
University of Tubingen, Hoppe-Seyler-Srr. 3, D-72076 Tubingen,
Germany.
116
Copyright 0 1998 by the American Neurological Association
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