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Consequences of a novel caveolin-3 mutation in a large German family.

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Consequences of a Novel Caveolin-3
Mutation in a Large German Family
Dirk Fischer, MD,1 Anja Schroers, MD,2 Ingmar Blümcke, MD,3 Horst Urbach, MD,4 Klaus Zerres, MD,5
Wilhelm Mortier, MD,5 Matthias Vorgerd, MD,2 and Rolf Schröder, MD1
Mutations in the human caveolin-3 gene (cav-3) on chromosome 3p25 have been described in limb girdle muscular dystrophy, rippling muscle disease, hyperCKemia, and distal myopathy. Here, we describe the genetic, myopathological, and
clinical findings in a large German family harboring a novel heterozygous mutation (GAC3 GAA) in codon 27 of the cav-3
gene. This missense mutation causes an amino acid change from asparagine to glutamate (Asp27Glu) in the N-terminal
region of the Cav-3 protein, which leads to a drastic decrease of Cav-3 protein expression in skeletal muscle tissue. In
keeping with an autosomal dominant mode of inheritance, this novel cav-3 mutation was found to cosegregate with neuromuscular involvement in the reported family. Ultrastructural analysis of Cav-3–deficient muscle showed an abnormal
folding of the plasma membrane as well as multiple vesicular structures in the subsarcolemmal region. Neurological examination of all nine subjects from three generations harboring the novel cav-3 mutation showed clear evidence of rippling
muscle disease. However, only two of these nine patients showed isolated signs of rippling muscle disease without muscle
weakness or atrophy, whereas five had additional signs of a distal myopathy and two fulfilled the diagnostic criteria of a
coexisting limb girdle muscular dystrophy. These findings indicate that mutations in the human cav-3 gene can lead to
different and overlapping clinical phenotypes even within the same family. Different clinical phenotypes in caveolinopathies
may be attributed to so far unidentified modifying factors/genes in the individual genetic background of affected patients.
Ann Neurol 2003;53:233–241
Caveolin proteins (21–24kDA) are principal components of caveolae, which are flask-shaped invaginations
of the plasma membrane participating in signal transduction events and vesicular traffic processes (for reviews
see Anderson1 and Galbiati and colleagues2). Caveolin
proteins have been implicated to have an essential role in
the formation of caveolae by acting as a scaffolding proteins, which organize and concentrate specific caveolininteracting lipids and proteins. The mammalian caveolin
gene family comprises caveolin-1, -2, and -3.3 Although
caveolin-1 and -2 are predominantly expressed or coexpressed in adipocytes, fibroblasts, and endothelial cells,
caveolin-3 protein (Cav-3) expression is confined to cardiac, skeletal, and smooth muscle tissue.3–5
Mutations in the caveolin-3 gene (cav-3) were first
identified in autosomal dominant limb girdle muscular
dystrophy (LGMD 1C).6 The main clinical features of
LGMD1C patients are mild to moderate proximal
muscle weakness, exercise-related muscle cramps, and
calf hypertrophy. Cav-3 mutations also were reported
in asymptomatic hyperCKemia7,8 and autosomal domFrom the 1Department of Neurology, University of Bonn, Bonn;
2
Department of Neurology, Klinikum Bergmannsheil, University of
Bochum, Bochum; 3Institute of Neuropathology, University of Erlangen–Nürnberg, Erlangen; 4Department of Radiology, University
of Bonn, Bonn; 5Institute of Human Genetics, University of
Aachen, Aachen; and 6Department of Pediatrics, St. Joseph Hospital, University of Bochum, Bochum, Germany.
inant inherited rippling muscle disease.9 The clinical
hallmarks of rippling muscle disease (RMD) are
percussion-induced rapid muscle contractions (PIRC),
localized (painful) muscle moundings, and percussionor stretching-induced rolling movements across a muscle group (rippling).10,11 Although calf hypertrophy
was reported in rippling muscle disease, muscle weakness and wasting is usually absent. Furthermore, a
cav-3 mutation recently was described to cause a distal
myopathy (DM).12 Here, we describe the genetic, morphological, and clinical analysis a large German family
with a novel heterozygous missense cav-3 gene mutation, leading to rippling muscle disease, distal myopathy, and LGMD 1C within the same kinship.
Subjects and Methods
Patients and Clinical Criteria
Nineteen members of a large German kinship underwent clinical and molecular genetic evaluation and underwent neurological examination using a standardized protocol to determine
symptoms and clinical involvement (Medical Research Coun-
Address correspondence to Dr Schröder, Department of Neurology;
University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. E-mail: rolf.schroeder@ukb.uni-bonn.de
Received Aug 7, 2002, and in revised form Oct 4. Accepted for
publication Oct 7, 2002.
© 2003 Wiley-Liss, Inc.
233
Fig 1. Family pedigree and segregation of the cav-3 mutation: phenotype of affected subjects as indicated above. (open squares and
circles) Unaffected family members. N ⫽ not affected and mutation excluded. (question mark) Haplotype and phenotype not
known. LGMD ⫽ limb girdle muscular dystrophy.
cil [MRC] scale, modified from Brooke and colleagues13). For
the diagnosis of rippling muscle disease, distal myopathy, and
LGMD, the following criteria were used: (1) rippling muscle
disease: percussion-induced rapid muscle contractions in at
least two muscles of the upper and lower extremities as well as
the presence of at least one of the following features: muscle
mounding, muscle rippling, or elevated CK11; (2) distal myopathy: weakness confined to distal limb muscles; (3) LGMD:
muscle weakness more pronounced in proximal than in distal
muscle groups. Furthermore, we reevaluated the detailed clinical descriptions of five patients from the same kinship that
had been reported in 196214 and classified them according to
the above described criteria. Possible rippling muscle disease
was diagnosed when signs of muscular hyperirritability (at that
time referred to as myotonia) were reported.
Molecular Genetic Analysis
Written and informed consent was obtained from all 19 subjects from the reported family. DNA extraction from blood
samples and cav-3 mutation analysis was performed as described previously.15
Muscle Biopsy, Histochemistry, and
Electron Microscopy
An open diagnostic biopsy taken from the left vastus lateralis
muscle of the index patient was performed in a peripheral hospital. Normal control muscle was obtained from a patient who
underwent muscle biopsy for diagnosis of neuromuscular symptoms but ultimately was deemed to be normal by means of
combined clinical, serological, electrophysiological, and histological criteria. Six-micrometer-thick cryostat sections of snapfrozen unfixed muscle were stained with hematoxylin and eosin,
Gomori trichrome, nicotine-ATPase at pH 4.3, 4.5, and 9.5,
cytochrome c oxidase, and succinate dehydrogenase by standard
procedures.16 To estimate neuronal nitric oxide synthase
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(nNOS) activity in skeletal muscle, we performed the NADPH
diaphorase activity assay on 10␮m frozen muscle sections as described recently.17 For standard electron microscopy, muscle tissue was fixed in 3% glutaraldehyde with HEPES buffer (pH
7.5), postfixed in 1% osmium, dehydrated, and embedded in
Spurr’s resin. Ultrathin sections were contrasted with uranyl acetate and lead citrate and examined using a Zeiss 900 electron
microscope (Zeiss, Oberkochen, Germany).
Antibodies and Immunohistochemistry
For immunohistochemistry, frozen sections (6␮m) were fixed
in acetone at ⫺20°C for 10 minutes and dried before further
processing. Antibodies were diluted in phosphate-buffered saline containing 1% bovine serum albumin. The following primary mouse monoclonal antibodies were used: caveolin-3,
nNOS (Transduction, Lexington, UK), dys-1, dys-2, dys-3,
␣-sarcoglycan, ␤-sarcoglycan, ␥-sarcoglycan and ␦-sarcoglycan,
dysferlin, ␤-dystroglycan (Novocastra, Newcastle, UK), and
desmin (DAKO, Glostrup, Denmark). The binding of these
antibodies was detected with Texas Red–labeled secondary antibodies (Jackson ImmunoResearch Laboratories, Hamburg,
Germany) or DAB (Vectastain ABC kit; Vector Laboratories/
Alexis, Grunberg, Germany) according to the recommendations of the manufacturers. Slides were mounted in Mowiol
(Calbiochem, Bad Soden, Germany) containing 0.1% Dabco
(Sigma Chemical Gmbh, Munich, Germany). All specimens
were examined and pictures were digitally acquired using a
Nikon E800 microscope (Nikon, Düsseldorf, Germany)
equipped with a charge-coupled device camera.
Immunoblotting
Total protein extracts were prepared from frozen muscle tissue
by homogenization in 20 vol of 5% sodium dodecyl sulfate,
15% glycerol, 50mM sodium phosphate, pH 6.8/40mM
DTT, 5mM EDTA, 5mM EGTA, and 3mM phenylmethyl
Fig 2. Cav-3 mutation detection (A). In contrast with normal controls (top panel), sequence analysis of affected family members
(bottom panel) showed a novel heterozygous GAC3 GAA missense mutation at codon 27 of exon 1 in the cav-3 gene leading to
an amino acid change from asparagine to glutamine. (B) cav-3 protein structure and previously described cav-3 mutations.
LGMD ⫽ limb girdle muscular dystrophy.
sulfonyl fluoride and incubated at 95°C for 10 minutes. These
extracts were separated by 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis. Acrylamide to bisacrylamide solutions (29:1) were purchased from Gibco-BRL (Karlsruhe,
Germany). Ten percent gels were run for 5 hours at 30mA.
Proteins were transferred electrophoretically onto polyvinylidene difluoride membranes (NeoLab, Heidelberg, Germany)
using 25mM sodium borate, 1mM EDTA, pH 9.2 as transfer
buffer in a wet blot chamber (BioRad, Munich, Germany).
Immunodetection of Cav-3 using the mouse monoclonal antiserum (1:100) was performed with peroxidase-coupled secondary antibodies (1:30,000; Dianova, Hamburg, Germany)
and visualization using the Supersignal enhanced chemiluminescence kit (Pierce, St. Augustin, Germany).
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) was performed on a
1.5T scanner (Gyroscan NT-Intera; Philips, Best, The Netherlands). Coronal and axial T1-weighted spin-echo (TR, 509
milliseconds; TE, 14 milliseconds; slice thickness, 7mm) and
axial T2-weighted fast spin echos (TR, 509 milliseconds; TE
14 milliseconds; slice thickness, 7mm) with and without fat
suppression were used to study muscle involvement.
Results
Family Pedigree and cav-3 Mutation Analysis
The pedigree of the reported family is shown in Figure
1. DNA mutation analysis of the index patient (see Fig
Fischer et al: Novel cav-3 Mutation
235
Fig 3. Cav-3 immunostaining of diseased (A) and normal (B) human skeletal muscle. Note the drastic decrease of cav-3 expression
when compared with normal controls. Dysferlin immunostaining with reduced sarcolemmal reaction in cav-3–deficient muscle (C).
Dysferlin staining of normal skeletal muscle (D). Bars ⫽ 60␮m.
1, Patient III.10) showed a novel heterozygous missense mutation residing in exon 1 of the cav-3 gene
(GAC3 GAA base exchange at codon 27), causing an
amino acid change from asparagine to glutamate
(Asp27Glu) within the N terminus of the protein (Fig
2). This mutation was found in 9 of 19 family members analyzed so far. In keeping with an autosomal
dominant mode of inheritance, the novel cav-3 mutation was found to cosegregate with neuromuscular involvement in the reported family (see Fig 1). The single base change in codon 27 was not detected in 10
unaffected family members or in 200 normal control
chromosomes.
Cav-3 Protein Expression
Immunhistochemical analysis of skeletal muscle from
our index patient showed a drastic decrease of sarcolemmal cav-3 protein expression (Fig 3A and B).
Cav-3 was completely absent in greater than 95% of
muscle fibers. A sarcolemmal staining spanning the
whole circumference of the muscle fiber pattern was
seen in only a few very small fibers, whereas Western
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blot analysis failed to detect Cav-3 protein (data not
shown). Because cav-3 was reported to directly interact with dysferlin,18 we assessed dysferlin expression
by immunostaining and Western blotting. Immunostaining for dysferlin showed an abnormal staining
pattern with reduced sarcolemmal cytoplasmic immunoreactivity (see Fig 3C and D). In contrast, Western
blotting using total protein extracts from skeletal
muscle tissue from our index patient showed a normal dysferlin protein expression level compared with
controls (data not shown). NADPH diaphorase activity assay showed no detectable difference compared
with normal controls (data not shown). Immunhistochemical analysis using antibodies directed against
dystrophin (days 1–3), sarcoglycans (␣, ␤, ␥, ␦),
␤-dystroglycan, and desmin gave normal results (data
not shown).
Morphological Analysis of cav-3–Deficient
Skeletal Muscle
Morphological analysis of a muscle biopsy from the
index patient showed mild myopathic changes con-
Fig 4. Morphological analysis of cav-3–deficient muscle. (A) H and E staining of skeletal muscle from the index patient (III.10)
showed mild myopathic changes consisting of a slight increase of endomysial connective tissue, pathological fiber-size variability, and
increased internalization of nuclei. Bar ⫽ 100␮m. (B) H and E staining of skeletal muscle from a patient (III.2) with RMD and
limb girdle muscular dystrophy additionally showed an abnormal cytoplasmic configuration representing either fiber degeneration or
excessive fiber splitting. Bar ⫽ 50␮m. (C) Ultrastructural analysis of skeletal muscle from the index patient showed the presence of
multiple vesicular structures in the subsarcolemmal region (arrow) and an abnormal folding of plasma membrane (bar ⫽ 0.3␮m).
sisting of a slight increase of endomysial connective
tissue, pathological fiber-size variability, and increased
internalization of nuclei (Fig 4A). Patients III.2, IV.3,
and IV.4 had a diagnostic muscle biopsy more than
15 years ago. Reevaluation of hematoxylin and eosin–
stained muscle specimens from these patients showed
similar changes to those of the index patient. In addition, in muscle from Patient III.2 some fibers
showed an abnormal cytoplasmic configuration representing either fiber degeneration or excessive fiber
splitting, which were not seen in the four other muscle biopsies from the same family (see Fig 4B).
Ultrastructural analysis of skeletal muscle from our
index patient showed multiple vesicular structures in
the subsarcolemmal region. In addition, an abnormal
folding of the sarcolemma and plasmamembrane was
seen in greater than 60% of all fibers analyzed (see Fig
4C). However, because most muscle fibers were seen in
a contracted state, it is currently unclear whether these
changes are related to the primary cav-3 deficiency.
Phenotype Analysis: Rippling Muscle Disease, Limb
Girdle Muscular Dystrophy, and Distal Myopathy
in the Same Family
Neurological examination of nine subjects (including
the index patient) harboring the novel cav-3 mutation
showed clear evidence of rippling muscle disease, calf
hypertrophy, and elevated CK levels (Table). All gave a
history of painful muscle cramps and stiffness since
childhood. Reports of pain and stiffness were always
related to exercise or movements and never occurred at
rest. There was no family history of cardiac problems
or malignant hyperthermia. On neurological examination, we were able to elicit percussion-induced rapid
Fischer et al: Novel cav-3 Mutation
237
Table. Summary of Clinical Features in the Reported Family
RMD
Age
Gender (yr)a CK Mutat PIRC Moundings Rippling Neck Shoulder Elbow
Patient
I.2 (8)
I.3 (14)b
I.4 (15)b
II.1 (9)b
II.2 (10)b
F
M
F
F
M
71
69
63
45
39
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
m
m
m
m
m
⫹
⫹
⫹
⫹
⫹
?
?
?
?
?
II.6
III.1 (11)
M
F
63
57
364
168
⫹
⫹
⫹
⫹
⫹
⫹
⫹
⫹
III.2 (12)
M
55
206
⫹
⫹
⫹
⫹
III.10
III.11
IV.3
M
F
F
37 556
32 1390
30 188
⫹
⫹
⫹
⫹
⫹
⫹
⫹
⫹
⫹
⫺
⫺
⫹
IV.4
F
27
233
⫹
⫹
⫹
⫹
⫺
IV.18
IV.19
F
F
5
2
412
853
⫹
⫹
⫹
⫹
⫹
⫹
⫺
⫺
⫺
⫺
b
F
⫹ns
⫹ns
⫹ns
F Ab, ER
F
IR
F Ab, Ad,
ER
⫺
⫺
F 4⫹ ER 4⫺
F
F
F
F
F
Weakness
Hand Finger Hip
⫹ns
⫹ns
⫹ns
⫺
E
⫺
Ab 4⫹
F 4,
⫺
E 4⫹
Knee Ankle
⫹ns
F
F, E
⫹ns Ab, F
F
⫹ns Ab, F
F
⫹ns
F
⫺
⫺
⫺
⫺
⫺
⫺
pRMD;
pRMD;
pRMD;
pRMD;
pRMD;
LGMD
LGMD
LGMD
LGMD
LGMD
⫺
⫺
DF 4
RMD; DM
Ab 4, F 4 ⫹ DF 4 RMD; LGMD
Ad 4,
F4
Ab 4, F 4 ⫹ DF 4 RMD; LGMD
F4
F4
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
⫺
F 4⫹ Ab 4⫺,
Ad 4,
ER 4
⫺
⫺
⫺
⫺
⫺
⫺
DF
DF
DF
DF
DF
Diagnosis
DF 4
DF 4
DF
4⫹
DF
4⫹
⫺
⫺
RMD; DM
RMD; DM
RMD; DM
RMD; DM
RMD; ⫺
RMD; ⫺
a
At examination.
Clinical data collected from Richter and Zeh.14
Ab ⫽ abduction; Ad ⫽ adduction; CK ⫽ creatine kinase in U/L; DF ⫽ dorsiflexion; E ⫽ extension; ER ⫽ external rotation; F ⫽ flexion;
IR ⫽ internal rotation; LGMD ⫽ limb girdle muscular dystrophy; m ⫽ myotonia-like reaction on percussion; nd ⫽ not done; pRMD ⫽
possible RMD; ⫺ ⫽ absent, ⫹ ⫽ present; ⫹ ns ⫽ present but not further specified in Richter and Zeh.14
Numbers in parentheses indicate identification number of affected individual used in Richter and Zeh.14
b
muscle contractions in upper and lower extremities
muscles (Fig 5). In contrast, classic rippling was seen
only in five patients.
However, only the youngest two patients (aged 2
and 5 years) showed isolated signs of rippling muscle
disease without muscle weakness or atrophy. In five of
these nine subjects there were additional signs of a distal myopathy defined by ankle dorsiflexor weakness
(Fig 6B). One patient also showed slight atrophy of
intrinsic hand muscles indicating upper limb involvement (see Fig 6C). To assess the extent of distal muscle
involvement, we conducted MRI scans of his lower legs
for Patient III.11, which documented atrophy and
fatty degeneration in his anterior leg compartment and
medial gastrocnemius muscles on T2-weighted images
(see Fig 6D). Furthermore, two patients had predominantly proximal muscle weakness consistent with the
clinical picture of a coexisting limb girdle muscular
dystrophy. MRI scans of pelvis and thighs of Patient
III.1 with rippling muscle disease and LGMD showed
predominant signal abnormalities in hip abductor, hip
adductor, rectus femoris, and hamstring muscles indicating atrophy and fatty degeneration of these muscle
groups (Fig 7A and B).
One member of the family drew our attention to an
Š
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February 2003
Fig 5. Percussion-induced rapid muscle contractions: the clinical hallmark of RMD. Note the flexion of the ring finger in
response to mild percussion of the flexor digitorum muscle.
Fig 6. Clinical and magnetic resonance imaging (MRI) features of a patient with RMD and DM. (A) calf hypertrophy, (B) weakness of foot dorsiflexion, (C) slight atrophy of intrinsic hand muscles, (D) MRI signal abnormalities (arrowheads) in the anterior
leg compartment and medial gastrocnemius muscle on T2-weighted images (Patient II.7).
article published in 1962, which contains a detailed
clinical description of five affected subjects from earlier
generations of the kinship (see Fig 1 and the Table).14
All reported patients had signs of proximal muscle
weakness (see Fig 7C and D) as well as signs of muscular hyperirritability, which, at that time, were interpreted as signs of myotonia. Patients III.1 and III.2
with rippling muscle disease and coexisting LGMD
also were reported in this publication, and it is noteworthy that both displayed signs of predominant proximal muscle weakness in their early stages of the
disease.
Discussion
In this study, we identified a novel heterozygous mutation (GAC3 GAA) in codon 27 of the human cav-3
gene that causes an amino acid change from asparagine
to glutamate (Asp27Glu) in the N-terminal region of
the cav-3 protein. This novel cav-3 missense mutation,
found in nine members of the reported family, coseg-
regated with muscular involvement following an autosomal dominant mode of inheritance.
Immunhistochemical and Western blot analysis
showed a severe reduction (⬎95%) of Cav-3 protein expression in skeletal muscle from our index patient,
which can be attributed to a dominant negative effect of
the cav-3 mutation. In keeping with this hypothesis,
previous studies demonstrated that Cav-3 mutant/Cav-3
wild-type proteins form unstable, high molecular protein
aggregates that are retained within the Golgi complex
where they undergo rapid degradation via the 26S-proteasome–dependent pathway.19,20 A recent study provided evidence of direct interaction of Cav-3 and dysferlin.18 Analogous to the phenotypic variability in
caveolinopathies, mutations of the human dysferlin gene
also have been shown to cause limb girdle muscular dystrophy type 2B, Miyoshi myopathy, and a distal anterior
compartment myopathy.21–23 Immunhistochemical
analysis of Cav-3–deficient muscle from our index patient showed a decreased sarcolemmal dysferlin staining.
Fischer et al: Novel cav-3 Mutation
239
Fig 7. Clinical and magnetic resonance imaging (MRI) features of two patients with RMD and LGMD. (A, B) MRI
signal abnormalities (arrowheads) in hip and thigh muscles
with predominant changes in hip abductor, hip adductor, rectus femoris, and hamstring muscles on T2-weighted images
(III.1). (C, D) Marked proximal weakness with scapula alata
and wasting of thigh muscles of a patient (I.3) with probable
RMD and coexisting LGMD published 1962 (with kind permission of the Schweizer Archiv für Neurologie und Psychiatrie, Verlag Bäbler, Bern Switzerland).
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Because our Western blot analysis provided no evidence
of detectable changes in dysferlin protein expression
when comparing Cav-3–deficient muscle with normal
controls, our immunhistochemical findings imply secondary changes in the subcellular distribution of dysferlin in response to the markedly decreased Cav-3 protein
expression. Although the functional relevance of these
findings awaits further elucidation, it is tempting to
speculate that the failure to translocate dysferlin to the
sarcolemma, though secondary in its nature, may be an
important event in the pathogenesis of caveolinopathies.
Morphological analysis of five muscle specimens from
five affected subjects showed mild myopathic changes
consisting of slight increase of endomysial connective tissue, pathological fiber-size variability, and an increased
internalization of nuclei. It is noteworthy that the muscle biopsy from our index patient, who showed clinical
signs of rippling muscle disease and coexisting distal myopathy was taken from a proximal, clinically unaffected
muscle group. Given the marked signal abnormalities in
the anterior leg compartment and medial gastrocnemius
muscles on T2-weighted MRI scans in Patient III.11
with rippling muscle disease and distal myopathy, one
would expect more pronounced histopathological
changes in clinically affected distal muscle groups.
Therefore, the extent of histopathological changes in
Cav-3–deficient muscle tissue appears likely to reflect
the duration and extent of clinical involvement of individual muscles chosen for a diagnostic biopsy.
Further ultrastructural analysis of skeletal muscle
from our index patient showed an abnormal folding of
the plasma membrane and multiple vesicular structures
in the subsarcolemmal region. The latter finding is in
line with a recently published study on ultrastructural
changes in LGMD1C, which provided evidence that
the prominent vesicular structures are caused by a
striking disorganization of the T-tubular system openings at the subsarcolemmal level.24 For the clinical presentation of RMD, it is tempting to speculate that
structural and functional changes of the T-tubular system, which may trigger an inappropriate calcium release from the sarcoplasmatic reticulum, are related to
muscular hyperirritability thereby causing clinical
symptoms oft percussion-induced rapid muscle contractions, mounding, and rippling.
Neurological evaluation of the reported family demonstrated marked intrafamilial clinical variability of subjects harboring the novel cav-3 missense mutation. Rippling muscle disease with coexisting distal myopathy was
the most frequently encountered phenotype that, though
not exclusively, was clustered in one branch of the family, whereas both cases with rippling muscle disease and
coexisting LGMD were exclusively found in another
branch of the reported kindred. In addition, the youngest two patients showed isolated signs of rippling muscle
disease without muscle weakness or atrophy. Analogous
to previous reports showing that an identical dysferlin
mutation can lead to LGMD 2B as well as Miyoshi myopathy in one family,21,22 our study demonstrates that
the novel cav-3 missense mutation can lead to rippling
muscle disease, rippling muscle disease and distal myopathy, and rippling muscle disease and LGMD within the
same kinship. Therefore, Cav-3 deficiencies do not always have a distinct clinical phenotype but may overlap.
Beyond the reported family, these findings imply that
patients with cav-3 deficiencies as well as their family
members should carefully be evaluated or reevaluated for
signs of muscular hyperirritability. In the absence of classic rippling, neurological examination should focus on
mounding and percussion-induced rapid muscle contractions, the latter being the most sensitive clinical signs
for rippling muscle disease.10
Intrafamilial and interfamilial phenotypic variability
in caveolinopathies, dysferlinopathies, and any other
neuromuscular diseases is a central, though unresolved,
issue. In our opinion, the reported kinship with clustering of distinct phenotypes in different branches of the
family would be very attractive for further genetic analysis looking for specific polymorphism that influence the
individual phenotypic presentation of Cav-3 deficiency.
We thank all the patients for their willingness to participate in
this study. In addition, the excellent technical assistance of
K. Kappes-Horn, M. Altenschmidt, and K. Tolksdorf is gratefully
acknowledged. Furthermore, we thank W. Nettekoven for the excellent photographs.
References
1. Anderson RG. The caveolae membrane system. Annu Rev Biochem 1998;67:199 –225.
2. Galbiati F, Razani B, Lisanti MP. Caveolae and caveolin-3 in
muscular dystrophy. Trends Mol Med 2001;7:435– 441.
3. Engelman JA, Zhang X, Galbiati F, et al. Molecular genetics of
the caveolin gene family: implications for human cancers, diabetes, Alzheimer disease, and muscular dystrophy. Am J Hum
Genet 1998;63:1578 –1587.
4. Tang Z, Scherer PE, Okamoto T, et al. Molecular cloning of
caveolin-3, a novel member of the caveolin gene family expressed predominantly in muscle. J Biol Chem 1996;271:
2255–2261.
5. Song KS, Scherer PE, Tang Z, et al. Expression of caveolin-3 in
skeletal, cardiac, and smooth muscle cells. Caveolin-3 is a component of the sarcolemma and co-fractionates with dystrophin
and dystrophin-associated glycoproteins. J Biol Chem 1996;
271:15160 –15165.
6. Minetti C, Sotgia F, Bruno C, et al. Mutations in the
caveolin-3 gene cause autosomal dominant limb-girdle muscular
dystrophy. Nat Genet 1998;18:365–368.
7. Merlini L, Carbone I, Capanni C, et al. Familial isolated hyperCKaemia associated with a new mutation in the caveolin-3
(CAV-3) gene. J Neurol Neurosurg Psychiatry 2002;73:65– 67.
8. Carbone I, Bruno C, Sotgia F, et al. Mutation in the CAV3
gene causes partial caveolin-3 deficiency and hyperCKemia.
Neurology 2000;54:1373–1376.
9. Betz RC, Schoser BG, Kasper D, et al. Mutations in CAV3
cause mechanical hyperirritability of skeletal muscle in rippling
muscle disease. Nat Genet 2001;28:218 –219.
10. Torbergsen T. A family with dominant hereditary myotonia,
muscular hypertrophy, and increased muscular irritability, distinct from myotonia congenita thomsen. Acta Neurol Scand
1975;51:225–232.
11. Vorgerd M, Bolz H, Patzold T, et al. Phenotypic variability in
rippling muscle disease. Neurology 1999;52:1453–1459.
12. Tateyama M, Aoki M, Nishino I, et al. Mutation in the
caveolin-3 gene causes a peculiar form of distal myopathy. Neurology 2002;58:323–325.
13. Brooke MH, Griggs RC, Mendell JR, et al. Clinical trial in
Duchenne dystrophy. I. The design of the protocol. Muscle
Nerve 1981;4:186 –197.
14. Richter K, Zeh W. Eine Sippe mit myotoner Dystrophie und Status dysraphicus. Schweiz Arch Neurol Psychol 1962;90:57–73.
15. Vorgerd M, Ricker K, Ziemssen F, et al. A sporadic case of
rippling muscle disease caused by a de novo caveolin-3 mutation. Neurology 2001;57:2273–2277.
16. Dubowitz V, Brooke MH. Muscle biopsy. A modern approach.
Philadelphia: Saunders, 1973.
17. Sunada Y, Ohi H, Hase A, et al. Transgenic mice expressing
mutant caveolin-3 show severe myopathy associated with increased nNOS activity. Hum Mol Genet 2001;10:173–178.
18. Matsuda C, Hayashi YK, Ogawa M, et al. The sarcolemmal
proteins dysferlin and caveolin-3 interact in skeletal muscle.
Hum Mol Genet 2001;10:1761–1766.
19. Galbiati F, Volonte D, Minetti C, et al. Phenotypic behavior of
caveolin-3 mutations that cause autosomal dominant limb girdle muscular dystrophy (LGMD-1C). Retention of LGMD-1C
caveolin-3 mutants within the golgi complex. J Biol Chem
1999;274:25632–25641.
20. Galbiati F, Volonte D, Minetti C, et al. Limb-girdle muscular
dystrophy (LGMD-1C) mutants of caveolin-3 undergo ubiquitination and proteasomal degradation. Treatment with proteasomal inhibitors blocks the dominant negative effect of
LGMD-1C mutanta and rescues wild-type caveolin-3. J Biol
Chem 2000;275:37702–37711.
21. Weiler T, Bashir R, Anderson LV, et al. Identical mutation in
patients with limb girdle muscular dystrophy type 2B or Miyoshi myopathy suggests a role for modifier gene(s). Hum Mol
Genet 1999;8:871– 877.
22. Illarioshkin SN, Ivanova-Smolenskaya IA, Greenberg CR, et al.
Identical dysferlin mutation in limb-girdle muscular dystrophy
type 2B and distal myopathy. Neurology 2000;55:1931–1933.
23. Illa I, Serrano-Munuera C, Gallardo E, et al. Distal anterior
compartment myopathy: a dysferlin mutation causing a new
muscular dystrophy phenotype. Ann Neurol 2001;49:130 –134.
24. Minetti C, Bado M, Broda P, et al. Impairment of caveolae
formation and T-system disorganization in human muscular
dystrophy with caveolin-3 deficiency. Am J Pathol 2002;160:
265–270.
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