Calpain 3 (CAPN3)

Calpain, a heterodimer consisting of a large and a small subunit, is a major intracellular protease, although its function has not been well established. CAPN3 encodes a muscle-specific member of the calpain large subunit family that specifically binds to titin. Alternate promoters and alternative splicing result in multiple transcript variants encoding different isoforms and some variants are ubiquitously expressed. In melanocytic cells CAPN3 gene expression may be regulated by MITF.Defects in CAPN3 are the cause of limb-girdle muscular dystrophy type 2A (LGMD2A). LGMD2A is an autosomal recessive degenerative myopathy characterized by progressive symmetrical atrophy and weakness of the proximal limb muscles and elevated serum creatine kinase.