DMD and Duchenne muscular dystrophy: Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder that is caused by mutations in the dystrophin gene, and affects approximately 1 in 3,500-5,000 males.1 The life expectancy in DMD in developed countries has improved in the last decade with survival extending to mid-30s.2, 3 Although progressive loss of skeletal muscle strength is a clinical hallmark of DMD, cardiac dysfunction due to cardiac muscle weakness is often the cause of death in DMD.