Types of Muscular Dystrophy and Neuromuscular Diseases

What are the types of muscular dystrophy?

Neuromuscular disorders are conditions that affect the nerve, muscle, or neuromuscular junction. (This is where the nerve talks to the muscle.) Muscular dystrophy is a group of inherited diseases that cause weakness. They also cause wasting away of muscle tissue. There are many types of muscular dystrophy. Each type leads to loss of strength, disability that gets worse, and possible deformity.

The most common type is Duchenne muscular dystrophy. The next most common is Becker muscular dystrophy.

There are nine major types of muscular dystrophy. Each type differs in the muscles affected, the age of onset, and its rate of progress. They are named for the muscles that are affected.

Type

Age at onset

Symptoms, rate of progress, and life expectancy

Becker

Teen to early adulthood

Symptoms are almost the same as Duchenne, but less severe. It progresses more slowly than Duchenne. Survival goes into mid to late adulthood. Becker disease is almost always limited to males. This is the same as with Duchenne.

Congenital

Birth

Symptoms include general muscle weakness and possible joint deformities. The disease progresses slowly. It causes a shortened life span.

Duchenne

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.

Distal

Ages 40 to 60

Symptoms include weakness and wasting of muscles of the hands, forearms, and lower legs. The progress is slow. It rarely leads to total disability.

Emery-Dreifuss

Childhood to early teens

Symptoms include weakness and wasting of shoulder, upper arm, and shin muscles. Joint deformities are common. The progress is slow. Sudden death may occur from cardiac problems.

Facioscapulohumeral

Childhood to early adults

Symptoms include facial muscle weakness and weakness with some wasting of shoulders and upper arms. Progress is slow with periods of rapidly getting worse. Life span may be many decades after onset.

Limb-Girdle

Late childhood to middle age

There are many forms with varying degrees of symptoms which include weakness and wasting that affects shoulder girdle and pelvic girdle first. Progress is slow. Death is most often due to cardiopulmonary problems.

Myotonic

Ages 20 to 40

Symptoms include weakness of all muscle groups and delayed relaxing of muscles after contraction. It affects the face, feet, hands, and neck first. Progress may be slow, sometimes spanning 50 to 60 years. A form that affects infants causes more severe problems.

Oculopharyngeal

Ages 40 to 70

Symptoms affect muscles of eyelids and throat causing throat muscles to weaken. Over time, this causes inability to swallow and severe weight loss from lack of food. Progress is slow.

What are other neuromuscular diseases?

Disease

Disease

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)

Inflammatory myopathies:

• Dermatomyositis
• Polymyositis
• Inclusion body myositis

Diseases of peripheral nerve:

• Charcot-Marie-Tooth disease
• Dejerine-Sottas disease
• Friedreich's ataxia
• Toxic neuropathy
• Neuropathy due to medical disease (such as diabetes, kidney disease, or cancer)

Diseases of the neuromuscular junction:

• Myasthenia gravis
• Lambert-Eaton syndrome
• Botulism

Metabolic diseases of the muscle:

• Acid maltase deficiency
• Carnitine deficiency
• Carnitine palmityl transferase deficiency
• Debrancher enzyme deficiency
• Lactate dehydrogenase deficiency
• Mitochondrial myopathy
• Myoadenylate deaminase deficiency
• Phosphorylase deficiency
• Phosphofructokinase deficiency
• Phosphoglycerate kinase deficiency

Less common myopathies:

• Central core disease
• Hyperthyroid myopathy
• Myotonia congenita
• Myotubular myopathy
• Nemaline myopathy
• Paramyotonia congenita
• Periodic paralysis-hypokalemic-hyperkalemic