Although the reduction or deficiency of dystrophin is the primary pathological cause of Duchenne muscular dystrophy (DMD, a lethal form of skeletal muscular dystrophy characterized by progressive wasting of the skeletal muscle191), dystrophic skeletal muscle fibers from a murine animal model of DMD (i.e., mdx mice) show reduced expression of CASQ-like proteins of 150–220 kDa (with no change in the expression level of RyR1, DHPR, SERCA1a, and CASQ1)192. The gene discussed is CASQ1; the disease is Duchenne muscular dystrophy.