Does the severity of the LGMD2A phenotype in compound heterozygotes depend on the
combination of mutations?
Sáenz A1,*,, Ono Y2,*, Sorimachi H2, Goicoechea M1,8, Leturcq F3, Blázquez L4, GarcíaBragado F5, Marina A6, Poza JJ7, Azpitarte M1, Doi N2, Urtasun M7, Kaplan JC3, López deMunain A7
1

Biodonostia Institute, 7Department of Neurology, Hospital Donostia, San Sebastián, Spain.

2

Calpain Project, Department of Advanced Science for Biomolecules, Tokyo Metropolitan Institute ofMedical Science, Tokyo, Japan3

5 Institut Cochin, CNRS UMR 8104, Inserm U 1016 Université Paris Descartes, Paris, France.

4

Department of Gene Therapy and Hepatology, Center for Investigation in Applied Medicine (CIMA),
Pamplona, Spain

5

Department of Neuropathology, Hospital Virgen del Camino, Pamplona, Spain.

6

Instituto de Biomedicina de Valencia-CSIC, CIBERER, Valencia, Spain.

8

CIBERNED, Instituto Carlos III, Madrid, Spain.

* Both authors equally contributed to the work

To whom correspondence should be addressed: Biodonostia Institute, Hospital Donostia, Pº Dr Begiristain
s/n, 20014 San Sebastián, Basque Country, Spain. Tel: +34 943 007061; Fax: +34 943 007061; E-mail:amets.saenzpena@osakidetza.net

KEY WORDS: LGMD2A, calpainopathy, calpain-3, phenotype, protein activity.
Abbrebiations: LGMD2A: Limb-girdle muscular dystrophy type 2A, GMW: GardnerMedwin-Walton, MRI: Magnetic resonance imaging, mCL: m-calpain catalytic subunit,
EF-3: third EF-hand motif, Capn3CS/CS:calpain-3 knock-in mice.
Conflict of Interest: None declared.

Acknowledgments
We would like to thank Jacques Beckmann for critical comments on the manuscript, andNathalie Deburgrave and Caroline Beugnet for their technical assistance. S.A. is supportedby the Fondo Investigaciones Sanitarias (FIS), the Health Research Fund of the Spanish

Ministry of Health and the Fundación Vasca de Innovacion e Investigaciones Sanitarias(BIOEF). B.L. is a pre-doctoral fellow supported by the Basque Governments’ Departmentof Education, Universities and Research. G.M. is a pre-doctoral fellow supported by
CIBERNED. This study was in part supported by the Gipuzkoako Foru Aldundia(Berrikuntzarako eta Jakintzaren Gizarterako Departamentua to S.A.), MEXT.KAKENHI(18076007 to H.S; 22770139 to Y.O.), JSPS.KAKENHI (20370055 to H.S.), a Research
Grant (20B-13) for Nervous and Mental Disorders from the Ministry of Health, Labour andWelfare (to H.S.), and by a Takeda Science Foundation research grant (to H.S.).

Abstract
Introduction: Limb-girdle muscular dystrophy type 2A (LGMD2A), is caused by a
deficiency of calpain-3/p94. While the symptoms in most LGMD2A patients are generally
homogeneous, some variation in the severity and progression of the disease have beenreported. Methods: We describe two patients carrying the same combination of compound
heterozygous mutations (pG222R/pR748Q) and whose symptoms were exceptionallybenign compared to homozygotes with each missense mutation. Results: The benign
phenotype observed in association with the combined pG222R and pR748Q mutations
suggested that it may result from a compensatory effect of compound heterozygosity rather
than the individual mutations themselves. Our analyses revealed that these two mutations
exert different effects on the protease activity of calpain-3, suggesting "molecularcomplementation" in these patients. Discussion: We propose several hypotheses to explain
how this specific combination of mutations may rescue the normal proteolytic activity of
calpain-3, resulting in an exceptionally benign phenotype.

Limb-girdle muscular dystrophy type 2A (LGMD2A) is the most frequentautosomal recessive muscular dystrophy1-4 and it is caused by a deficit of calpain-3/p94, acalcium-dependent protease whose exact physiological functions and substrates are poorly
understood. Disease onset in most LGMD2A patients occurs in the second decade of life,
beginning with proximal muscle weakness, and most patients become wheelchairdependent after several years of disease progression. Despite the general uniformity of thesymptoms in most LGMD2A patients, some differences in severity and progression havebeen reported. Indeed, these differences involve variation in the sites affected or theevolution of the disease (metabolic myopathy symptoms, clinical adult-type spinal
muscular atrophy, predominant distal involvement, etc…).5-11
In patients in whom the disease has progressed for over 25 years, the number ofwheelchair-dependent patients is higher among carriers of two null mutations than thosewith at least one missense mutation.12 The precise phenotype-genotype relationship isdifficult to elucidate, as there appears to be some variability among patients with the same
mutation(s), in some cases even within the same family. 9-12
We found compound heterozygous patients showing exceptionally benign
symptoms compared to homozygotes with each missense mutation. The different
phenotypic consequences of this combination of missense mutations (in homozygous orcompound heterozygous state) was analyzed both clinically and biochemically. Our results
suggest that "molecular complementation" between specific calpain-3 missense mutants
may result in a more benign form of the disease.

Materials and methods
Patients—Patients were recruited from the Muscular Dystrophy Database of the LGMD2A
Molecular Database of the Biodonostia Institute at the Donostia Hospital. For inclusion in
the study, patients had to fulfill the following criteria: 1) confirmation of both missense
mutations at CAPN3; 2) aged 30 years or over with well documented clinical statusaccording to Gardner-Medwin-Walton (GMW) functional scale13 and 3) atypically benign
at 30 years of age, with a GMW score of less than III.
Out of 295 LGMD2A patients, two fulfilled all three criteria, both of whom had compound
heterozygous pG222R and pR748Q missense mutations. The clinical characteristics ofthese patients are summarized in Table 1, including the age at onset and the results of themuscle biopsies. Mutation screening was carried out according to Richard et al.14
To evaluate the benign phenotype, the cases fulfilling the following criteria were also
screened: 1) at least one allele containing a pG222R or pR748Q missense mutation on the
CAPN3 gene; and 2) 30 or more years of LGMD2A history with a well defined clinicalstatus according to GMW scale.

Western blotting of tissue—Western blotting was performed as previously described15 withminor modifications. Frozen tissue samples were weighed and homogenized with 19w/v oftreatment buffer (0.125mol/L Tris; 4% sodium dodecyl sulphate (SDS); 10% glycerol;
0.1mol/L ethylenediaminetetraacetic acid (EDTA) and 5% β-Mercaptoetanol) in a
TissueLyser mixer-mill disruptor (Quiagen) and loaded onto a SDS-polyacrylamide gel.
The membranes were probed with the following antibodies in duplex immunoblot analysis:NCL-2C4 (for calpain-3, Novocastra); Ad1/20A6 (for α-sarcoglycan, Novocastra).

cDNA Constructs—Expression vectors for human calpain-3 and its mutants wereconstructed as described previously16, and after verification by full-length DNA sequencing,
they were transfected into COS7 cells by electroporation using a Gene Pulser (Bio-Rad).
Cells were incubated for 60-72 hours at 37ºC and harvested for further analysis.

Western blotting of transfected COS7 cells—Cells were harvested in homogenizing buffer(20 mM Tris/Cl [pH 8.0], 1 mM EDTA [pH 8.0], 1 mM dithiothreitol). Equal amounts ofprotein from each sample were resolved by SDS-PAGE, transferred onto an Immobilon-Ptransfer membrane (Millipore). Gels are also stained by Coomassie brilliant blue to ensure
the equality of loaded protein amount. Membranes were incubated with goat anti-calpain-3pIS2 antibody (for calpain-317, or a rabbit anti-150K-fodrin-Nterm antibody (for the 150kDa -fodrin fragment specifically proteolyzed by calpain).18

Results
Out of 295 cases, two patients showed significantly benign clinical features (Table1), both of whom carried the pG222R and pR748Q mutations, exhibiting compound
heterozygosity. To examine the potential link between this genotype and the benign
phenotype, patients from previous studies with at least one of these mutations (pG222R or
pR748Q) were screened according to the same criteria described above but with GMW<III.
There were 11 such patients, including two homozygous for the pG222R mutation and two
homozygous for the pR748Q mutation. These patients exhibited little phenotypic variation

and all but two of them were wheelchair bound, most by the third decade of their life,
reflecting the severity of the phenotype associated with pG222R and pR748Q missense
mutations.
Western blot analysis of muscle biopsies from the patient P2 with thepG222R/pR748Q mutations revealed almost normal level of 94 kDa band for calpain-3(data not shown, Table 1). The same trend was observed for one of the patientshomozyogous for the pG222R mutation from our previously studied series (data notshown).
To address the apparent discrepancy in the phenotype-genotype correlation
observed between the compound heterozygotes and the homozygotes for pG222R and
pR748Q missense mutations, calpain-3 proteins with these mutations were expressed in
COS7 cells. When wild-type (WT) calpain-3 was expressed, it underwent rapid andexhaustive autolysis, and only a weak 94-kDa band and a faint 55-kDa autolytic fragment
was detected in Western blots, as previously reported.19 The full-length pG222R mutant
calpain-3 protein was stably expressed, and its autolytic activity was almost totallyabolished (Figure 1). Conversely, only a very faint 94-kDa pR748Q mutant calpain-3 band
was evident. Moreover, this pR748Q mutant calpain-3 may have enhanced autolytic
activity compared with the WT form, both the full-length 94-kDa protein and the 55-kDa
autolytic fragment were detected more weakly than the WT calpain. However, autolysis ofthese proteins occurred too rapidly to compare them precisely.
WT calpain-3 but not the mutant forms, such as pC129S and pR769Q, are reported
to proteolyse endogenous fodrin when expressed in COS7 cells.16 By contrast, pG222R
showed no proteolytic activity against fodrin and only very weak activity was observed forthe pR748Q mutant when compared to the WT control. Surprisingly, when pG222R andpR748Q were co-expressed, they exhibited greater fodrinolytic activity than that observed
when each mutant was expressed alone. These findings suggest that the combination of thepG222R and pR748Q mutations provokes the acquisition of unexpected activity in a gainof-function manner (Figure 2).

Discussion
The two compound heterozygous cases described here are clearly more benign thanother cases analyzed to date, both in terms of disease progression and the GMW functionalscore in relation to patient age. Despite the exceptionally benign clinical findings, MRI
images (data not shown) were highly suggestive of a LGMD2A type in both cases andpathogenic mutations at CAPN3 were confirmed. In patients where clinical examination
reveals very benign symptoms and western blot analysis of calpain-3 shows an almost
normal 94-kDa band, patients are likely to be mis-diagnosed as not having LGMD2A. This
raises the possibility of the existence more undiagnosed patients with this benign form of
LGMD2A.
Given that patients homozygous for the pG222R or pR748Q mutation show a very
severe phenotype, the benign phenotype observed for the compound heterozygotes isunlikely to be due to the mutations themselves. This is the first report showing that the
combination of these mutations, both of which are associated with severity in homozygotes,
results in a benign phenotype. Although several benign phenotypes have been associatedwith specific mutations,7,9-11 in most cases missense mutations were found in at least one of
the alleles, suggesting that calpain-3 function was partially retained in skeletal muscle.

When their expression was assessed using COS7cells, the pG222R mutation almost
completely abolished the autolytic activity of calpain-3 whereas the pR748Q mutant
showed autolytic activity comparable to (or possibly greater than) that of the WT control.
Gly222 of calpain-3 corresponds to Gly198 in the rat m-calpain catalytic subunit (mCL),
which plays an important role in breaking/turning the α-helix close to the junction of theprotease subdomains IIa and IIb (also known as domains I and II, respectively) in the 3D
structure of active m-calpain.20, 21 Thus, the conformation of subdomains IIa and IIb isprobably mis-aligned by the pG222R mutation, resulting in the inactivation of calpain-3.
Arg748 is located in the “F-helix” (the helix after the Ca2+-binding loop) of the third EFhand motif (EF-3) in domain IV, and it corresponds to Arg628 in the rat mCL. In the 3D
protein structure, Arg628 is very close to D362 in domain III (the distance between theclosest N and O atoms of Arg628 and Asp362, respectively, is 3.03 Å), indicating that theseresidues generate a salt bridge. Thus, the pR748Q mutation of calpain-3 most likely
disrupts the interaction between domains III and IV, resulting in an incorrect conformationof these domains.
When expressed in COS7 cells, the pR748Q mutant demonstrated significantly lessfodrinolytic activity than the WT calpain-3. As previously described for other domain IV
mutations in LGMD2A patients, such as pR744G and pR769Q, pR748Q may have greater
autolytic activity than the WT protein, which in turn may produce functional defects.16
The structure-function relationships of calpain-3 mutants demonstrate that both
mutations are deleterious, consistent with the severe phenotypes of the pG222R and
pR748Q homozygotes. Thus, it could be hypothesized that the benign effect of thepG222R/pR748Q mutation combination is due to functional complementation between

these specific mutations. Indeed, fodrinolytic activity in COS7 cells co-expressing pG222R
and pR748Q mutations is greater than that of cells expressing either pG222R or pR748Q
alone, and is comparable to that of the cells co-expressing the WT form and the pC129S
mutant. Hypothetical scenarios of molecular complementation between pG222R and
pR748Q are described below.
(a) Dimer hypothesis:
The p94 protein may form a homodimer in specific situations, for example, verysoon after being activated. This is witnessed by the formation of a p94 domain IV
homodimer.22 Domains III~IV are important for substrate-recognition and/or titin-binding,and this region is affected/altered in the pR748Q, but not the pG222R mutant. We
previously demonstrated that in some cases, titin can act as a scaffold for calpain-3
proteolysis of substrates.23 Although the pG222R mutant form of calpain-3 cannot
proteolyse substrates, it can recognize substrates and/or bind to titin, while the proteasedomain of dimerized pR748Q mutant calpain-3 can proteolyze substrates. Thus, the“canonical” functions of calpain-3 may be partially restored by the formation of a
pG222R/pR748Q heterodimer.
(b) Inhibitor hypothesis:
The pC129S and pG222R calpain mutants may also act as competitive inhibitors ofautolysis. If pR748Q causes unregulated/upregulated autolytic activity, by acting as a
substrate for pR748Q autolytic activity, the pG222R mutant could suppress the rate of
autolytic turnover of pR748Q to a level similar to that of WT p94, resulting in normal
calpain-3 function.
(c) Hybrid hypothesis:

Autolysis of calpain-3 occurs at the NS, IS1 and IS2 regions. Nicking in IS1 does
not cause immediate dissociation of the molecule but it causes it to retain its active
molecular state.17 Similarly, association of the N-terminal (34-274aa, from NS to IS1) andC-terminal (323-821aa, from IS1 to C-term) autolysed fragments has been described.24
Given that Gly222 and Arg748 reside in the N-terminal and C-terminal autolyzed
fragments, respectively, and supposing that pG222R is proteolyzed intermolecularly by
pR748Q, it is possible that the other halves of each mutant molecule co-associate toreconstitute an intact (WT) calpain-3 molecule (Figure 3). Titin has plural adjacent bindingsites for calpain-3 which could facilitate such an exchange by acting as a scaffold forcalpain-3. Furthermore, the propensity of calpain-3 to form a dimer may also be
significant.23
These hypotheses were constructed to explain how the specific combination of
mutations rescues, at least in part, the proteolytic activity of calpain-3. It is also possiblethat the compensatory effect of this combination of mutations affects other functions ofcalpain-3. Recent studies highlighting novel functions of calpain-3 suggest that structural
integrity of calpain-3 plays certain roles in skeletal muscle.26,27 In addition, it is not an
excluded possibility that deficits at the levels other than protein, e.g., mRNA metabolism,are caused by mutations in CAPN3. In other words, the severity of LGMD2A could bevaried due to the combination of secondary effects of the mutations that are primarily
abrogating protease activity of calpain-3 protein.
Obviously, additional genetic and biochemical data will be required to ascertain therelevance of these hypotheses. Rescue of the phenotypes of calpain-3 knock-in(Capn3CS/CS) mice, which express a structurally intact but protease-dead calpain-3:C129S

mutant, by other mutants theoretically competent for intermolecular compensation would
be one of the approaches to validate our hypotheses in vivo. However, our results dosuggest that certain combinations of missense mutations undergo molecular compensation,
thereby ameliorating disease symptoms. This compensatory effect is ascribed to the domain
structure of calpain-3 with sequence insertions, where we propose that two mutations
located before and after the IS1 region complement each other. As the exact functions andsubstrates of calpain-3 remain unknown, it will be necessary to elucidate further roles forcalpain-3 to determine the validity and significance of the hypotheses proposed.

REFERENCES
1.

Vainzof M, Passos-Bueno MR, Pavanello RC, Marie SK, Oliveira AS, Zatz M
Sarcoglycanopathies are responsible for 68% of severe autosomal recessive limb-girdle
muscular dystrophy in the Brazilian population.J Neurol Sci. 1999;164:44-9.

2.

Topaloğlu H, Dinçer P, Richard I, Akçören Z, Alehan D, Ozme S et al. Calpain-3
deficiency causes a mild muscular dystrophy in childhood. Neuropediatrics 1997; 28:
212-216.

3.

Richard I, Brenguier L, Dinçer P, Roudaut C, Bady B, Burgunder JM et al. Multiple
independent molecular etiology for limb-girdle muscular dystrophy type 2A patientsfrom various geographical origins. Am J Hum Genet 1997; 60: 1128-1138.

4.

de PF, Vainzof M, Passos-Bueno MR, de Cássia M, Pavanello R, Matioli SR et al.
Clinical variability in calpainopathy: what makes the difference? Eur J Hum Genet
2002; 10: 825-832.

5.

Starling A, de PF, Silva H, Vainzof M, Zatz M. Calpainopathy: how broad is the
spectrum of clinical variability? J Mol Neurosci 2003; 21: 233-236.

6.

Shirafuji T, Otsuka Y, Kobessho H, Minami N, Hayashi Y, Nishino I, et al. [Case of
LGMD2A (calpainopathy) clinically presenting as Miyoshi distal myopathy). Rinsho
Shinkeigaku 2008; 48: 651-655.

7.

Pollitt C, Anderson LV, Pogue R, Davison K, Pyle A, & Bushby KM. The phenotype
of calpainopathy: diagnosis based on a multidisciplinary approach. Neuromuscul
Disord 2001; 11: 287-296.

8.

Penisson-Besnier I, Richard I, Dubas F, Beckmann JS, Fardeau M. Pseudometabolic
expression and phenotypic variability of calpain deficiency in two siblings. Muscle
Nerve 1998; 21: 1078-1080.

9.

Hermanova M, Zapletalova E, Sedlackova J, Chrobáková T, Letocha O, Kroupová I etal.. Analysis of histopathologic and molecular pathologic findings in Czech LGMD2A
patients. Muscle Nerve 2006; 33: 424-432.

10. Fanin M, Fulizio L, Nascimbeni AC, Spinazzi M, Piluso G, Ventriglia VM et al..
Molecular diagnosis in LGMD2A: mutation analysis or protein testing? Hum Mutat
2004; 24: 52-62.
11. Chae J, Minami N, Jin Y, Nakagawa M, Murayama K, Igarashi F et al.. Calpain-3 genemutations: genetic and clinico-pathologic findings in limb-girdle muscular dystrophy.
Neuromuscul Disord 2001; 11: 547-555.
12. Saenz A, Leturcq F, Cobo AM, Poza JJ, Ferrer X, Otaegui D et al. LGMD2A:
genotype-phenotype correlations based on a large mutational survey on the calpain-3
gene. Brain 2005; 128: 732-742.

13. Gardner-Medwin D Walton JN. The clinical examination of voluntary muscles. 1974;
517-560.
14. Richard I, Broux O, Allamand V, Fougerousse F, Chiannikulchai N, Bourg N et al..
Mutations in the proteolytic enzyme calpain-3 cause limb-girdle muscular dystrophy
type 2A. Cell 1995; 81: 27-40.
15. Anderson LV, Davison K, Moss JA, Richard I, Fardeau M, Tomé FM et al..
Characterization of monoclonal antibodies to calpain-3 and protein expression inmuscle from patients with limb-girdle muscular dystrophy type 2A. Am J Pathol 1998;
153: 1169-1179.
16. Ono Y, Shimada H, Sorimachi H, Richard I, Saido TC, Beckmann JS et al.. Functional
defects of a muscle-specific calpain, p94, caused by mutations associated with limbgirdle muscular dystrophy type 2A. J Biol Chem 1998; 273: 17073-17078.
17. Ono Y, Torii F, Ojima K, Doi N, Yoshioka K, Kawabata Y et al. Suppresseddisassembly of autolyzing p94/CAPN3 by N2A connectin/titin in a genetic reporter
system. J Biol Chem 2006; 281: 18519-18531.
18. Saido TC, Yokota M, Nagao S, Yamaura I, Tani E, Tsuchiya T et al. Spatial resolutionof fodrin proteolysis in postischemic brain. J Biol Chem 1993; 268: 25239-25243.
19. Sorimachi H, Toyama-Sorimachi N, Saido TC, Kawasaki H, Sugita H, Miyasaka M etal. Muscle-specific calpain, p94, is degraded by autolysis immediately after translation,
resulting in disappearance from muscle. J Biol Chem 1993; 268: 10593-10605.
20. Moldoveanu T, Gehring K, Green DR. Concerted multi-pronged attack by calpastatin to
occlude the catalytic cleft of heterodimeric calpains. Nature 2008; 456: 404-408.
21. Hanna RA, Campbell RL, Davies PL. Calcium-bound structure of calpain and its
mechanism of inhibition by calpastatin. Nature 2008; 456: 409-412.
22. Ravulapalli R, Diaz BG, Campbell RL, Davies PL. Homodimerization of calpain-3
penta-EF-hand domain. Biochem J 2005; 388: 585-591.
23. Hayashi C, Ono Y, Doi N, Kitamura F, Tagami M, Mineki R, et al. Multiple molecularinteractions implicate the connectin/titin N2A region as a modulating scaffold for
p94/calpain-3 activity in skeletal muscle. J Biol Chem 2008 ; 283: 14801-14814.
24. Taveau M, Bourg N, Sillon G, Roudaut C, Bartoli M, Richard I. Calpain-3 is activatedthrough autolysis within the active site and lyses sarcomeric and sarcolemmal
components. Mol Cell Biol 2003; 23: 9127-9135.
25. Strobl S, Fernandez-Catalan C, Braun M Huber, Masumoto H, Nakagawa K et al. The
crystal structure of calcium-free human m-calpain suggests an electrostatic switch
mechanism for activation by calcium. Proc Natl Acad Sci U S A 2000; 97: 588-592.

26. Kramerova I, Kudryashova E, Wu B, Ottenheijm C, Granzier H, Spencer MJ. Novelrole of calpain-3 in the triad-associated protein complex regulating calcium release inskeletal muscle. Hum Mol Genet 2008; 17:3271-80.
27. Ojima K, Ono Y, Ottenheijm C, Hata S, Suzuki H, Granzier H, Sorimachi H. Nonproteolytic functions of calpain-3 in sarcoplasmic reticulum in skeletal muscles. J Mol
Biol. 2011; 407: 439-49.

Titles and legends to figures
Figure 1: Effects of LGMD2A pathogenic mutations on calpain-3 autolysis. Closed andopen triangles indicate the full-length form and autolyzed/proteolyzed fragment of calpain3. Asterisks indicate non-specific signals. Autolytic activity of the proteins expressed isqualitatively shown by + and - below the blot (WT=+++; #: including proteolysis of
pC129S by WT calpain-3). The pG222R but not the pR748Q mutation inactives calpain-3
autolytic activity. The inactive pC129S mutant produced a stable 94-kDa band. "Mock"indicates the negative control transfected with the empty vector.
Figure 2: Protease activity against fodrin. The same sample as that described in Figure 1
was analyzed with an anti-150K-fodrin-Nterm antibody that specifically detects the Nterminus of fodrin proteolyzed by calpain. Open triangles indicate the 150-kDa fodrin
fragment proteolyzed by calpain-3. Fodrinolytic activity is indicated qualitatively by + and- according to the intensity of the proteolyzed fodrin bands (WT=+++). Note that the
C129S, G222R and R748Q mutants showed little or no activity. "Mock" and asterisks
indicate the negative control transfected with the empty vector and non-specific signals,
respectively.
Figure 3: A schematic representation of our hybrid hypothesis. The loci of G222R and
R748Q mutations in calpain-3 molecules are represented in green and blue, respectively.
The calpain-3 molecule is illustrated by the ribbon model, based on the reported 3-Dstructure of human m-calpain (1KFX25). All associations can be reversed (dissociation),
which is not indicated in the figure.

Table 1: Patient’s clinical information. Patient 1 was originally included in a previous study (Urtasun et al 1998).

Patient

P1
FemaleP2
Male

Age at onset

Current clinical status and Western Blot analysis(current age)of Biopsy sample

23
(43 )

20
(34)

Predominant

Current

MRI findings

GMW scale

3,370 U/L

Selective involvement of the posterior
compartment of the thigh and posteromedialcompartment of the legs.

II

5,000 - 8,000 U/L

Severe impairment of the hamstring and hip
adductors. Quadriceps and gracilis spared.

II

CK

Ambulant with a myopathic gait, hyperlordosis,
unable to climb stairs or get up from a chair.
Normal cardiac echography.
Western blot data not available.
Ambulant with moderate weakness of the pelvic
girdle.
Hypertrophy of quadriceps and mild
pseudohypertrophic features of scapular winging.
Pseudometabolic clinical pattern.
Western Blot analysis revealed normal/borderline
protein bands.

1