Muscular dystrophy is a group of conditions that cause progressive muscle weakness and loss of muscle mass. In muscular dystrophy, abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle. The most common type of muscular dystrophy, Duchenne muscular dystrophy (DMD), occurs mostly in boys. Symptoms usually appear between ages 2 and 5, … [Read more...] about What is Muscular Dystrophy and What are the Types?