It proves to be crucial for muscle cell homeostasis, as demonstrated in Limb-Girdle Muscular Dystrophy type 2A (LGMD2A, or calpainopathy), which is characterized by different CAPN3 point mutations and by muscle hypotrophy, hypoplasia and myonuclear apoptosis [2,3]. The gene discussed is CAPN3; the disease is autosomal recessive limb-girdle muscular dystrophy type 2A.