Partial α‐sarcoglycan deficiency with retention of the dystrophin‐glycoprotein complex in a LGMD2D family

In patients with sarcoglycan (SG) deficiency, a primary defect in any one of the four SG proteins usually leads to reduced expression of the whole SG complex. We report a limb-girdle muscular dystrophy type 2D family (LGMD2D), with variable phenotype, where a mutation in the alpha-SG gene resulted in the partial deficiency of alpha-SG alone. The normal expression of the other three SG proteins suggests that mutations close to the alpha-SG transmembrane domain might be less critical for complex integrity, and that weakness may occur despite its retention.