The muscular dystrophies (MD) are a group of more than 30 genetic diseases characterized by progressive weakness and degeneration of the skeletal muscles that control movement. Some forms of MD are seen in infancy or childhood, while others may not appear until middle age or later. The disorders differ in terms of muscle weakness, age of onset, rate of progression and pattern of inheritance.
Duchenne muscular dystrophy is the most common form. It primarily affects boys and is caused by the absence of dystrophin, a protein that helps maintain muscle. Onset is between 3 and 5 years, and the disorder progresses rapidly. Most boys are unable to walk by age 12, and later need a respirator to breathe. Girls in these families have a 50 percent chance of inheriting and passing the defective gene to their children.
Boys with Becker muscular dystrophy, which is similar to Duchenne MD but less severe have faulty or not enough dystrophin.
Facioscapulohumeral MD usually begins in the teenage years. It causes progressive weakness in muscles of the face, arms, legs and around the shoulders and chest. It progresses slowly and symptoms vary from mild to disabling.
Myotonic MD is the disorder's most common adult form and is typified by prolonged muscle spasms, cataracts, cardiac abnormalities and endocrine disturbances. Individuals with myotonic MD tend to have long, thin faces, drooping eyelids and a swan-like neck.
There is no specific treatment to stop or reverse any form of muscular dystrophy. Treatment may include:
- Physical therapy
- Respiratory therapy
- Speech therapy
- Orthopedic appliances for support
- Corrective orthopedic surgery
- Drug therapy
Drug therapy includes corticosteroids to slow muscle degeneration, anticonvulsants to control seizures and some muscle activity, immunosuppressants to delay some damage to dying muscle cells and antibiotics to fight respiratory infections. Some patients may benefit from occupational therapy and assistive technology. Others may need assisted ventilation to treat respiratory muscle weakness and a pacemaker for cardiac abnormalities.
For More Information
Parent Project for Muscular Dystrophy Research, Inc.
Muscular Dystrophy Association
FSH Society, Inc.
Source: National Institute of Neurological Disorders and Stroke