[Muscular dystrophy due to a mutation in the gene of alpha-sarcoglycan subunit of dystrophin associated protein complex].

Linkage studies have confirmed the existence of clinical an genetic heterogeneity among the muscular dystrophies due to adhalin deficiency. We present the clinical, histological and genetic characteristics in a case of primary adhalinopathy (deficiency of the 50 kD subunit or alpha-sarcoglycan). It was a 19 years-old woman, born of non consanguineous parents, who shows a long evolution myopathy with onset before age 7, a severe evolution and becoming wheelchair bound at 10 years. She showed evident calf pseudohypertrophy and serum creatinkinase (CK) levels were elevated (40-180 times the standard level). The histological pattern showed a destructed fascicular architecture in agreement with severe muscular dystrophy, normal staining with anti-dystrophin monoclonal antibodies and abnormal staining pattern with anti-adhalin antibodies. The molecular study evidenced an homozygous point mutation (Arg-->Cys) at position 77 of exon 3 of the gene coding for the 50 kD subunit of the alpha-sarcoglycan complex localised in chromosome 17. In the light of this case, we suggest a revision of the diagnostic orientation in the muscular dystrophies and we review the new taxonomy of the limb-girdle muscular dystrophies, remarking the clinical signs which could indicate a given genetic locus.