Muscular dystrophy is a genetic disorder characterized by the progressive degeneration of skeletal muscles. The main types are Duchenne MD, which affects boys and causes loss of walking ability by age 12, Becker MD which is similar but less severe, and facioscapulohumeral MD which begins in teens and causes weakness in the face, arms, shoulders and chest. Treatment focuses on physical, respiratory, and occupational therapy as well as drug therapy to slow muscle degeneration, but there is no cure. The prognosis depends on the type and severity but can range from mild symptoms and slow progression to severe disability or death in infancy.