Diagnosing limb-girdle muscular dystrophy type 2A by Western blot analysis

Abstract

Objective To evaluate Western blot analysis in diagnosing limb-girdle muscular dystrophy type 2A (LGMD2A). Methods The clinical records including their pathological and biochemical results of 4 patients with LGMD type 2 were reviewed. Histochemical and immunohistochemical staining were performed on muscle biopsy specimens from the four patients. The expressions of dysferlin and calpain-3 in muscles were analyzed by Western biol. Results All 4 LGMD patients shared some common clinical features, such as dorsal muscular atrophy of lower limbs and remarkably elevated CK. The immunohistochemical results showed partial or complete deficiency of dysferlin staining in all 4 LGMD patients. However, Western blot revealed that the calpain-3 protein in the muscle of patient 1 was completely absent, who was later diagnosed with LGMD2A. The other 3 patients had complete dysferlin deficiency with reduced calpain-3 expression and they were confirmed to be LGMD2B. Conclusions Western blot analysis of calpain-3 and dysfcrlin can be used to differentiate LGMD2A which shows absence of calpain-3 from other LGMD types which show dysferlin deficiency. Western blot is an invaluable method in clinical diagnosis of LGMD2A. Key words: Muscular dystrophies, limb-girdle; Blotting, western; Membrane proteins; Muscle proteins; Calpain