Muscular dystrophy is a group of inherited diseases characterized by weakness and wasting away of muscle tissue, with or without the breakdown of nerve tissue. There are 9 types of muscular dystrophy, with each type involving an eventual loss of strength, increasing disability, and possible deformity.
The most well known of the muscular dystrophies is Duchenne muscular dystrophy (DMD), followed by Becker muscular dystrophy (BMD).
Listed below are the 9 different 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
adolescence to early adulthood
Symptoms are almost identical to Duchenne, but less severe; progresses more slowly than Duchenne; survival into middle age. As with Duchenne, disease is almost always limited to males.
Symptoms include general muscle weakness and possible joint deformities; disease progresses slowly; shortened life span.
2 to 6 years
Symptoms include general muscle weakness and wasting; affects pelvis, upper arms, and upper legs; eventually involves all voluntary muscles; survival beyond 20s is rare. Seen in boys only. Very rarely can affect woman, who have much milder symptoms and a better prognosis.
40 to 60 years
Symptoms include weakness and wasting of muscles of the hands, forearms, and lower legs; progression is slow; rarely leads to total incapacity.
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.
20 to 40 years
Symptoms include weakness of all muscle groups accompanied by delayed relaxation of muscles after contraction; affects face, feet, hands, and neck first; progression is slow, sometimes spanning 50 to 60 years.
40 to 70 years
Symptoms affect muscles of eyelids and throat causing weakening of throat muscles, which, in time, causes inability to swallow and emaciation from lack of food; progression is slow.
Spinal muscular atrophies:
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
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