Introduction to Muscular Dystrophies and Related Disorders
Muscular dystrophies are a group of inherited muscle disorders in which one or more genes needed for normal muscle structure and function are defective, leading to muscle weakness of varying severity. Facioscapulohumeral dystrophy is the most common form of muscular dystrophy. Duchenne muscular dystrophy is the second most common and the most severe form. Becker muscular dystrophy is closely related to Duchenne dystrophy but starts later in a child's life and causes milder symptoms.
Other inherited muscle disorders include congenital myopathies, familial periodic paralysis, and glycogen storage diseases. Glycogen storage diseases are a group of rare inherited disorders in which muscles cannot metabolize sugars normally, so they build up large stores of glycogen (a starch that is formed from sugars).