Muscular dystrophy (MD) refers to a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal or voluntary muscles which control movement. The muscles of the heart and some other involuntary muscles are also affected in some forms of MD, and a few forms involve other organs as well.
The major forms of MD include myotonic, Duchenne, Becker, limb-girdle, facioscapulohumeral, congenital, oculopharyngeal, distal and Emery-Dreifuss. Duchenne is the most common form of MD affecting children, and myotonic MD is the most common form affecting adults.
MD can affect people of all ages. Although some forms first become apparent in infancy or childhood, others may not appear until middle age or later.
Is There Any Treatment?
There is no specific treatment for any of the forms of MD. Physical therapy to prevent contractures (a condition in which shortened muscles around joints cause abnormal and sometimes painful positioning of the joints), orthoses (orthopedic appliances used for support) and corrective orthopedic surgery may be needed to improve the quality of life in some cases.
The cardiac problems that occur with Emery-Dreifuss MD and myotonic MD may require a pacemaker. The myotonia (delayed relaxation of a muscle after a strong contraction) occurring in myotonic MD may be treated with medications such as phenytoin or quinine.
What Is the Prognosis?
The prognosis of MD varies according to the type of MD and the progression of the disorder. Some cases may be mild and very slowly progressive, with normal lifespan, while other cases may have more marked progression of muscle weakness, functional disability and loss of ambulation. Life expectancy may depend on the degree of progression and late respiratory deficit. In Duchenne MD, death usually occurs in the late teens to early 20s.
The National Institute of Neurological Disorders and Stroke is a component of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services.
