A drug inhibits the mitochondrial protease inducing calmitine deficiency in skeletal muscle of patients with Duchenne's muscular dystrophy and dy/dy dystrophic mice.

This study demonstrates that the cause of calmitine deficiency in dy/dy dystrophic mice and patients with Duchenne's muscular dystrophy (DMD) is the same; i.e., the absence of an inhibitor of calmitine-specific mitochondrial protease. This inhibitor, which is present in control mice and control subjects, prevented degradation of the protein. It is also shown that a drug (IP96) was capable in vitro of inhibiting calmitine-specific mitochondrial protease from muscle of DMD patients and dy/dy mice. This drug was also active in vivo in an experimental model of myopathy created in the normal mouse by a single injection of chlorpromazine, a myotoxic drug, which induced temporary calmitine degradation. Thus, it seems quite likely that IP96 prevents calmitine degradation by inhibiting the specific protease.