MUSCULAR-DYSTROPHY DUE TO A MUTATION IN T HE GENE OF ALPHA-SARCOGLYCAN SUBUNIT OF DYSTROPHIN-ASSOCIATED PROTEIN COMPLEX

Linkage studies have confirmed the existence of clinical an genetic he terogeneity 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 alp ha-sarcoglycan). It was a 19 years-old woman, born of non consanguineo us parents, who shows a long evolution myopathy with onset before age 7, a severe evolution and becomign wheelchair bound at 10 years, She s howed evident calf pseudohypertrophy and serum creatinkinase (CK) leve ls were elevated (40-180 time sthe standard level). The histological p attern showed a destructed fascicular architecture in agreement with s evere muscular dystrophy, normal staining with anti-dystrophin monoclo nal antibodies and abnormal staining pattern with anti-adhalin antibod ies. The molecular study evidenced an homozigous point mutation (Arg - -> Cys) at position 77 of exon 3 of the gene coding for the 50 kD subu nit of the alpha-sarcoglycan complex localised in chromosome 17. In th e light of this case, we suggest a revision of the diagnostic orientat ion in the muscular dystrophies and we review the new taxonomy of the limb-girdle muscular dystrophies, remarking the clinical signs which c ould indicate a given genetic locus.