Primary calpainopathy (LGMD2A, OMIM 253600), caused by mutations in the 40-kb CAPN3 gene (OMIM 114240, mapped to 15q15.1-q21.1), is the most frequent form of recessive LGMD, with a prevalence of 1∶15,000–1∶150,000 depending on the population [1]. The gene discussed is CAPN3; the disease is autosomal recessive limb-girdle muscular dystrophy type 2A.