Cardiac complications were identified in 9 patients (6.1%); 2 patients had hypertrophic cardiomyopathy, and the other cardiac manifestations included dilated cardiomyopathy, intracardiac thrombus, elevated creatine kinase (CK)-MB levels, mitral and tricuspid insufficiency, aortic valve insufficiency, left ventricular hypertrophy, and tachycardia. The gene discussed is MB; the disease is dilated cardiomyopathy.