[The two brothers' case of dilated cardiomyopathy with benign Duchenne type of progressive muscular dystrophy (Becker's type)].

The presence of myocardial involvement is rare in benign Duchenne type of progressive muscular dystrophy (Becker's muscular dystrophy). We describe two brothers suffering from Becker's muscular dystrophy, both of whom presented with dilated cardiomyopathy. The first case is a 39-year-old male who had suffered from gait disturbance from the age of 17. When 37 years old, he was found to have heart disease. When he first came to our hospital, pseudohypertrophy of the calves was present. Chest radiography, electrocardiogram, ultrasonocardiography and clinical feature indicated Becker's muscular dystrophy with dilated cardiomyopathy. The second case is the younger brother of the 37-year old male. He suffered from leg weakness. He came to our hospital with the chief complaint of discomfort of the anterior chest. Pseudohypertrophy of the calves was present. Chest radiography, electrocardiogram, ultrasonogram indicated dilated cardiomyopathy.