ABSTRACT-Muscular dystrophies are a group of diseases that make muscles weaker and less flexible over time. Duchenne muscular dystrophy (DMD) is the most common type. It’s caused by flaws in the gene that controls how the body keeps muscles healthy.The disease almost always affects boys, and symptoms usually begin early in childhood..Although there isn't a cure, the outlook for people with DMD is better than it has ever been. Years ago, children with the disease usually didn’t live beyond their teens. Today, they live well into their 30s, and sometimes into their 40s and 50s.