[Dystrophin abnormality in a patient with polymyositis associated with primary biliary cirrhosis and myocardial injury].

We have reported a 58-year-old Japanese female with polymyositis, primary biliary cirrhosis (PBC) and arrhythmia. In contrast to the previously reported 13 cases of polymyositis associated with PBC, symptoms and laboratory data abnormalities responded to oral administration of predonisolone. Interestingly, immunohistochemical and immunoblot analyses of biopsied skeletal muscle revealed diminished expression of dystrophin carboxyl-terminal domain in the sarcolemma, suggesting that, in analogy to Duchenne muscular dystrophy, secondary abnormality of the link between the basal lamina and cytoskeleton via the dystrophinglycoprotein complex may have played a role in the molecular pathogenesis of muscle fiber degeneration in this patient.