[The frequency of patients with adhalin deficiency in a muscular dystrophy patient population]

Immunocytochemical deficiency of alpha-sarcoglycan (adhalin) in the skeletal muscle that is associated with normal dystrophin expression has been called adhalinopathy. However, recent molecular biological and genetic studies revealed that alpha-sarcoglycan is one of four subunits of sarcoglycans (alpha-delta) or sarcoglycan complex. Mutations of any one of the genes of these subunits cause loss of sarcoglycan complex, and therefore they are now called sarcoglycanopathy or limb-girdle muscular dystrophy (LGMD) 2C-2F. The frequency of sarcoglycanopathy is about 5-10% of dystrophin-normal muscular dystrophy. Mutation of alpha-sarcoglycan gene is most frequent (34%) among the four sarcoglycan genes as shown in the tables. However, 38% of the patients with sarcoglycanopathy have no mutation, implying the presence of yet unknown sarcoglycan(s) and/or interacting protein(s) with sarcoglycan complex.