There are several different types of muscular dystrophy, diseases characterized by progressive muscle weakness and wasting.
Emery-Dreifuss muscular dystrophy chiefly affects the muscles used in movement (skeletal muscles) and the heart muscle. The earliest symptoms are joint deformities called contractures that restrict the movement of the elbows, ankles, and neck. Affected individuals also experience muscle weakness and wasting that progresses slowly from the upper arms and lower legs and moving into the shoulders and hips. By adulthood, most people with Emery-Dreifuss muscular dystrophy have heart problems. These come from abnormal heart rhythms and defects with the electrical signals that control the heartbeat. Untreated, these heart problems can lead to a slow heartbeat, fainting, increased risk of stroke, and increased risk of sudden death.
There are three different types of Emery-Dreifuss muscular dystrophy, distinguished by how the disease is inherited. The x-linked form is most common, affecting approximately one person out of one hundred thousand. The other two forms are rarer.
Emery-Dreifuss muscular dystrophy may also be known as EDMD, Emery-Dreifuss syndrome, and benign scapuloperoneal muscular dystrophy with early contractures.
Duchenne and Becker types of muscular dystrophy primarily affect the skeletal muscles and the muscles of the heart. These two types of muscular dystrophy have similar symptoms, including muscle weakness that appears in childhood and progresses rapidly. Heart problems usually begin in the teenage years and can become life threatening. The Duchenne type is often more severe and progresses more rapidly after appearing in early childhood; the Becker type has milder symptoms with a wide range of variation and may appear later in childhood.
Duchenne muscular dystrophy is the most common form of the disease in children. Together, the Duchenne and Becker types of muscular dystrophy affect one or two male children out of five thousand. In the United States, between four hundred and six hundred males are born with the disease each year. Females are rarely affected by these forms of muscular dystrophy.