Muscular dystrophy is a group of inherited diseases that causes weakness and wasting away of muscle tissue. They can also cause the breakdown of nerve tissue. There are multiple types of muscular dystrophy. Each type leads to loss of strength, increasing disability, and possible deformity.
The most common is Duchenne muscular dystrophy (DMD). The next most common is Becker muscular dystrophy (BMD).
Listed below are 9 major types of muscular dystrophy. Each type differs in the muscles affected, the age of onset, and its rate of progression. Some types are named for the affected muscles, including the following:
Age at onset
Symptoms, rate of progression, and life expectancy
Teen to early adulthood
Symptoms are almost the same as Duchenne, but less severe. It progresses more slowly than Duchenne. Survival goes into middle age. As with Duchenne, disease is almost always limited to males.
Symptoms include general muscle weakness and possible joint deformities. The disease progresses slowly. It causes a shortened life span.
Ages 2 to 6
Symptoms include general muscle weakness and wasting. It affects the pelvis, upper arms, and upper legs. Over time, it includes all voluntary muscles. Survival beyond the 20s is rare. It happens mostly in boys. Very rarely it can affect women, who have much milder symptoms and a better prognosis.
Ages 40 to 60
Symptoms include weakness and wasting of muscles of the hands, forearms, and lower legs. Progression is slow. It rarely leads to total disability.
Childhood to early teens
Symptoms include weakness and wasting of shoulder, upper arm, and shin muscles. Joint deformities are common. progression is slow. Sudden death may occur from cardiac problems.
Childhood to early adults
Symptoms include facial muscle weakness and weakness with some wasting of shoulders and upper arms. Progression is slow with periods of rapid deterioration. Life span may be many decades after onset.
Late childhood to middle age
Symptoms include weakness and wasting, affecting shoulder girdle and pelvic girdle first. Progression is slow. Death is usually due to cardiopulmonary complications.
Ages 20 to 40
Symptoms include weakness of all muscle groups and delayed relaxation of muscles after contraction. It affects the face, feet, hands, and neck first. Progression is slow, sometimes spanning 50 to 60 years. An infantile form causes more severe problems.
Ages 40 to 70
Symptoms affect muscles of eyelids and throat causing weakening of throat muscles. Over time, this causes inability to swallow and severe weight loss from lack of food. Progression is slow.
Motor neuron diseases:
Amyotrophic lateral sclerosis (ALS), or motor neuron disease
Infantile progressive spinal muscular atrophy
Intermediate spinal muscular atrophy
Juvenile spinal muscular atrophy
Adult spinal muscular atrophy
Progressive muscular atrophy
infectious myelitis (polio, West Nile)
Inclusion body myositis
Diseases of peripheral nerve:
Charcot-Marie tooth disease
Diseases of the neuromuscular junction:
Metabolic diseases of the muscle:
Acid maltase deficiency
Carnitine palmityl transferase deficiency
Debrancher enzyme deficiency
Lactate dehydrogenase deficiency
Myoadenylate deaminase deficiency
Phosphoglycerate kinase deficiency
Less common myopathies:
Central core disease