The muscle dystrophies are a group of genetic diseases that severely affect children and adults. Nine diseases of the muscles and nervous system can be classified as forms of MD. Physicians diagnose MD through muscle-strength tests, blood tests, electromyograms or biopsies. Muscle dystrophy is a group of nine neuromuscle diseases. This means it is related both to the nervous system and to the muscles. About 250,000 people in the United States have muscle dystrophy.
The most common is called myotonic dystrophy, also known as Steinert's disease. It affects both children and adults and progresses slowly from the first signs of weakness to marked deficiency. The most common muscle dystrophy affecting children is a severe form called Duchenne dystrophy. Usually diagnosed before age 5, Duchenne affects mostly boys. A child with this disorder is often described as especially clumsy and slow to crawl and walk. (Siegel, 1999)
Muscle dystrophy is genetic. It is inherited just like height and eye color. Scientists now know that a defective gene causes each type of muscle dystrophy. In some cases, if either parent carries a gene for muscle dystrophy, their child may develop it. Their child could also become a carrier. With some types of muscle dystrophy, however, both parents must pass along the defective gene.
Doctors routinely check children for muscle strength. When physicians suspect muscle dystrophy, they do specific tests to confirm it. Urine tests can show abnormal muscle metabolism but cannot be used to diagnose a specific disorder like muscle dystrophy. As muscles deteriorate in muscle dystrophy, muscle proteins leak out of the muscles and into the blood. (In normal muscles, the protein stays in the muscle.) By testing blood for the protein, muscle dystrophy may be detected, sometimes before weakness is noticeable...............
