Do some genetic mutations predict the development of dilated cardiomyopathy in patients with Becker's muscular dystrophy?

Becker’s muscular dystrophy (BMD) is an Xlinked recessive disease characterized by progressive muscular weakness. Gene mutations at the p21 band of the X chromosome coding for the protein dystrophin are found in BMD. Cardiac involvement in BMD was first recognized in 1966,1 and since then, dilated cardiomyopathy has been reported in patients with this disease. An 18-year-old man presented with dyspnea and orthopnea lasting for 3 months. On physical examination, he had mild proximal weakness, pes cavus, and all tendon reflexes were preserved with the exception of diminished ankle jerks. One of his older brothers died of congestive heart failure with mild neurologic symptoms. His parents