Muscular dystrophy (MD) is a term that applies to a group of hereditary muscle-destroying disorders. According to the Muscular Dystrophy Association, in 2006 some type of MD affected approximately one million Americans. Each type of the disease is caused by defects in the genes that play important roles in the growth and development of muscles. In MD the proteins produced by the faulty genes are abnormal, causing the muscles to slowly disintegrate. Unable to function properly, the muscle cells die and are replaced by fat and connective tissue. The symptoms of MD may not be noticed until as much as 50% of the muscle tissue has been affected. All of the different types of MD cause weakening and wasting of muscle tissues. They vary, however, in the usual age at the beginning of symptoms, rate of progression, and initial group of muscles affected. The most common childhood type, Duchenne Muscular Dystrophy, affects young boys, who show symptoms in early childhood and usually die from respiratory weakness or damage to the heart before becoming an adult. The gene is passed from the mother to her children. Females who inherit the defective gene generally do not have symptoms, they simply become carriers of the defective genes, and their children have a 50% chance of inheriting the disease. Other forms of MD become apparent later in life and are usually not fatal.…