Symptoms of muscular dystrophy vary depending on which type of the disease you have. Most types of muscular dystrophy affect voluntary muscles in the legs, arms, and torso, although other muscles may be affected, depending on the type. Generally, people with muscular dystrophy will experience muscle weakness and progressive crippling, which may eventually result in extreme difficulty with or loss of mobility. The age at which these symptoms occur also depends on the type of disease. Some diseases affect children and are very apparent before age 10, but others won't cause symptoms till adulthood.