Symptomatic dysferlin gene mutation carriers: characterization of two cases.
OBJECTIVE
To describe two symptomatic dysferlin gene mutation carriers.


METHODS
One patient had limb girdle weakness. His brother was diagnosed with limb girdle muscular dystrophy 2B with two mutations in the dysferlin gene (D625Y and E1734G). The second patient had distal weakness. He had two sons with Miyoshi myopathy with a homozygous mutation (G519R). We performed immunofluorescence (dystrophin, DAG proteins, dysferlin, caveolin-3), Western blot (dysferlin, caveolin-3, calpain-3), and real-time PCR (dysferlin) using skeletal muscle samples. We also studied dysferlin in peripheral blood monocytes (PBMs) by Western blot.


RESULTS
In addition to the muscle weakness, both patients showed elevated creatine kinase and abnormal muscle MRI. They presented a mutation in only one allele after screening of the whole gene (skeletal muscle and monocyte mRNA and genomic DNA). A muscle biopsy specimen showed moderate dystrophic changes and patchy dysferlin expression in the sarcolemma. Western blot of both PBMs and skeletal muscle demonstrated a significant reduction in dysferlin. All the other proteins including caveolin-3 and calpain-3 were normal. Real-time PCR showed normal levels of dysferlin mRNA vs the patients' affected relatives.


CONCLUSIONS
The diagnosis of symptomatic carriers of dysferlin mutations should be considered when a pathologic pattern of dysferlin protein is observed.
Illa
I
I
Servei de Neurologia i Laboratori de Neurologia Experimental, Hospital de la Santa Creu i Sant Pau i Institut de Recerca de HSCSP, Universitat Autonoma, Barcelona, Spain. iilla@santpau.es
De Luna
N
N
Domínguez-Perles
R
R
Rojas-García
R
R
Paradas
C
C
Palmer
J
J
Márquez
C
C
Gallano
P
P
Gallardo
E
E
D000328:Adult; D003402:Creatine Kinase / Q000378:metabolism; D004252:DNA Mutational Analysis; D000073939:Dysferlin; D005260:Female; D006580:Genetic Carrier Screening / Q000379:methods; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D006579:Heterozygote; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics*; D008875:Middle Aged; D009124:Muscle Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D018908:Muscle Weakness / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D009135:Muscular Diseases / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology*; D009154:Mutation / Q000235:genetics; D010375:Pedigree
C114839:DYSF protein, human; D000073939:Dysferlin; D005819:Genetic Markers; D008565:Membrane Proteins; D009124:Muscle Proteins; D003402:Creatine Kinase