What is this Condition?

Muscular dystrophy is actually a group of inherited disorders characterized by a progressive, symmetrical wasting away of skeletal muscles that occurs without causing pain or loss of feeling in the limbs. Paradoxically, these damaged muscles tend to enlarge because of connective tissue and fat deposition, giving a false impression of muscle strength.

So far, there is no cure for the condition, but there are four main types of muscular dystrophy, each with a different outcome. Duchenne type muscular dystrophy accounts for 50% of all cases. It generally strikes during early childhood and results in death by age 20. Becker’s muscular dystrophy is slower to develop, and people with it usually live into their 40s. The two last types (dystrophy of the face, shoulders, and arms and limb-girdle dystrophy) usually don’t shorten life expectancy.

What Causes it?

Muscular dystrophy is caused by various genes. The Duchenne and Becker types are carried by sex-linked genes affecting only men. Dystrophy of the face, shoulders, and arms and limb-girdle dystrophy are not sex-linked, so affect both sexes about equally.

What are its Symptoms?

Each type of muscular dystrophy causes progressive muscle deterioration, but incidence and severity varies in the following ways:

• The Duchenne type begins subtly, between ages 3 and 5. Children with this disorder have a waddling gait and difficulty climbing stairs, fall down often, can’t run properly, and their shoulder bones flare out (or “wing”) when they raise their arms.

Usually, a child with muscular dystrophy is confined to a wheel­chair by ages 9 to 12. Finally, progressive weakening of the heart muscle leads to death from sudden heart failure, respiratory failure, or infection.

• Although similar to the Duchenne type, the symptoms of Becker’s muscular dystrophy progress more slowly. Symptoms start around age 5, but children can still walk well beyond age 15 - sometimes into their 40s.

• Dystrophy of the face, shoulders, and arms is a slowly progressive and relatively harmless type that commonly occurs before age 10 but may develop during early adolescence. In the early stages, infants may not be able to suckle; children cant pucker their mouths or whistle or raise their arms above their heads. Affected children may have abnormal facial movements and a lack of facial movements when laughing or crying .

• Limb-girdle dystrophy follows a similarly slow course and often causes only slight disability. Usually, it begins between ages 6 and 10, causing muscle weakness first in the upper arm and pelvic muscles; then, the other common symptoms appear.

How is it Diagnosed?

The doctor examines the child, asks questions of the family, and orders certain tests. If another family member has muscular dystrophy, that persons symptoms usually tell a lot about the child’s future. If no one else has the disorder, tests of nerve activity in the affected muscles can reveal muscular dystrophy, and a muscle biopsy can show cell changes or cell fat and tissue deposits.

Medical centers with the most advanced immunologic and molecular biological techniques can accurately predict muscular dystrophy in the fetus. They can also test parents and relatives who may carry the genes for Duchenne and Becker’s muscular dystrophies.

How is it Treated?

No treatment has yet been found that can stop the progressive muscle deterioration of muscular dystrophy. However, orthopedic appliances, as well as exercise, physical therapy, and surgery to correct contractures, can help preserve the child or young adult’s mobility and independence for a time.

Family members who are carriers of muscular dystrophy should receive genetic counseling regarding the risk of transmitting this disease to their children.