Comparative expression of dysferlin, caveolin 3 and calpain 3. Expression of these proteins is primarily or secondarily affected in patients with defects in the caveolin 3 (CAV3) gene (limb girdle muscular dystrophy (LGMD)1C), the dysferlin (DYSF) gene (LGMD2B) and the calpain 3 (CAPN3) gene (LGMD2A). In a patient with mosaic expression of caveolin 3, fibres with loss of the protein also show reduced sarcolemmal labelling for dysferlin (a). (b) Immunoblot is a more reliable technique for diagnosis of LGMD2A and 2B. β-DG = β-dystroglycan; Dys-C = dystrophin C-terminal; α-SG = α-sarcoglycan.