Myotonic dystrophy is an inherited disorder of the muscles and other body systems. It is the most common form of muscular dystrophy in adults. Genetic changes are related to the following types of myotonic dystrophy. myotonic dystrophy, type 1 myotonic dystrophy, type 2 This disorder is characterized by progressive muscle wasting and weakness, particularly in the lower legs, hands, neck, and face. People with myotonic dystrophy often have prolonged muscle contractions (myotonia) and are not able to relax certain muscles after use. For example, a person may be unable to release a grip on a doorknob or handle. Other signs and symptoms of myotonic dystrophy may include clouding of the lens of the eye (cataracts), heart abnormalities, balding, and infertility. The features of this disorder can occur at any age, but usually develop during a person's 20s or 30s. One variation, called congenital myotonic dystrophy, can be noted at birth. The severity of these signs and symptoms varies widely between people, even between members of the same family. In general, the clinical features of type 2 myotonic dystrophy tend to be milder than those of type 1.