Muscular dystrophy (MD) refers to a group of more than 30 inherited diseases that cause muscle weakness and muscle loss. Some forms of MD appear in infancy or childhood, while others may not appear until middle age or later. The different muscular dystrophies vary in who they affect and the symptoms. All forms of MD grow worse as the person's muscles get weaker. Most people with MD eventually lose the ability to walk.

There is no cure for muscular dystrophy. Treatments include physical and speech therapy, orthopedic devices, surgery and medications. Some people with muscular dystrophy have mild cases that worsen slowly. Others cases are disabling and severe.