Muscular dystrophy (MD) is actually a group of more than thirty genetic diseases which are characterized by a progressive weakness as well as degeneration of the skeletal muscles that control movement. Some forms of muscular dystrophy are seen in childhood or even infancy, while other forms of muscular dystrophy may not appear until a person’s middle age or even later. The muscular dystrophy disorders differ in terms of the distribution and extent of muscle weakness. Some forms of muscular dystrophy also affect the cardiac muscle, for example. Some differ according to the age of onset, rate of progression, and any identifiable pattern of inheritance. The Duchenne muscular dystrophy is the most common form of muscular dystrophy and primarily affects boys. Duchenne is caused by the absence of dystrophin, a protein involved in maintaining the muscle integrity. Onset of Duchenne Muscular Dystrophy is between three and five years old, and the disorder progresses rapidly. Most boys with Duchenne Muscular Dystrophy are unable to walk by age twelve, and then still later need a respirator to breathe. Girls in these families have a fifty percent chance of inheriting the gene and then passing the defective gene along to their children. Boys with Becker MD, which is very similar to but less severe than Duchenne MD, will have faulty dystrophin or not enough dystrophin. Facioscapulohumeral MD usually begins the onset during the adolescent years. That muscular dystrophy causes progressive weakness in muscles of the face, legs, arms, and around the shoulders and chest. It progresses slowly and symptoms can vary from mild to disabling in their severity. Myotonic MD is the disorder's most common adult form and is characterized by prolonged muscle spasms, cardiac abnormalities, cataracts, and endocrine disturbances. Individuals with myotonic muscular dystrophy usually have very long, thin faces, drooping eyelids, and a long abnormal, swan-like neck.
There is no specific treatment to reverse nor stop any form of MD. Treatment for the various forms of MD may include respiratory therapy, physical therapy, speech therapy, orthopedic appliances to be used for support, and sometimes corrective orthopedic surgery. Drug therapy usually includes corticosteroids to slow the muscle degeneration, as well as anticonvulsants to control seizures and some muscle activity, immunosuppressant to delay damage to dying muscle cells, and antibiotics to fight infections. Individuals may show benefit from occupational therapy and assistive technology. Patients may need assisted ventilation to treat respiratory muscle weakness as well as a pacemaker for cardiac abnormalities that often develop with the progression of the muscular dystrophy.
The prognosis for people with MD will vary according to the type and progression of the dystrophy. Some dystrophy cases may be mild and progress very slowly over a normal lifespan, while others may produce severe and rapidly onsetting muscle weakness, functional disability, and loss of the ability to walk. Sometimes children with MD die in infancy while others live into adulthood with only a moderate disability.