Muscular dystrophy is a rare inherited muscle disease in which the muscle fibers are unusually susceptible to damage. The muscles, primarily the voluntary muscles, become progressively weaker. In the late stages of muscular dystrophy, muscle fibers often are replaced by fat and connective tissue.
There are several types of muscular dystrophy. The various types of the disease affect more than 50,000 Americans. Many are associated with specific genetic abnormalities.The most common muscular dystrophies appear to be due to a genetic deficiency of the muscle protein dystrophin. These types of the disease are called dystrophinopathies. They include:
· Duchenne's muscular dystrophy. This is the most severe form of dystrophinopathy. Duchenne's muscular dystrophy affects young boys. Signs and symptoms of the disease usually appear between the ages of 2 and 5. Children with the disease fall and have difficulty getting up off the floor. By late childhood, most are unable to walk. Most die by their late teens or early 20s, often from pneumonia, respiratory muscle weakness or cardiac complications.
· Becker's muscular dystrophy. This is a milder form of dystrophinopathy. It generally affects older boys and young men, and progresses more slowly, usually over several decades.
Duchenne's and Becker's muscular dystrophy are passed from mother to son through one of the mother's genes. The disease can "skip" a generation until another son inherits the defective gene. In some cases of Duchenne's and Becker's muscular dystrophies, the disease arises from a new mutation in a gene rather than from an inherited defective gene. Other types of muscular dystrophies can be handed on from generation to generation and affect males and females equally. Still others require a defective gene from both parents.
· Muscle weakness
· Apparent lack of coordination
· Inability to elevate your arms over your head
· Progressive crippling, resulting i...