The clinical spectrum of sarcoglycanopathies

A group of 204 muscular dystrophy patients were screened for immunohistochemical and biochemical α-sarcoglycan defect and their DNA was analyzed for pathogenetic mutation in the four sarcoglycan genes. We identified 21 patients with α-, β-, or γ-sarcoglycan gene mutations. Patients with α-sarcoglycan gene mutations were clinically heterogeneous and showed either a rapid progressive or a late-onset slow course. In the slowly evolving group, a residual α-sarcoglycan protein was present, and its level correlated with a milder disease course and significant later inability to stand up from the floor (p < 0.00005). Most patients with β- and γ- sarcoglycan gene mutations presented a severe clinical course. There is a considerably different pattern of muscle involvement and disease course in these disorders, compared with dystrophinopathies.