Muscular Dystrophy

These is a relatively rare group of progressive, genetic diseases that gradually destroy muscle tissue. The most common childhood forms are Duchenne muscular dystrophy and Becker muscular dystrophy; both affect about one in every 3,000 male babies born. Less common forms of muscular dystrophy can affect both boys and girls.

The muscular dystrophies are classified according to age at onset, rate of progression, heredity pattern and muscle groups affected. Symptoms vary with the type. The major forms of muscular dystrophy gradually weaken the muscles that control walking, manual dexterity and breathing. Other symptoms can include mental retardation and neurological and cardiac involvement.

WHEN SHOULD I SUSPECT MY CHILD HAS MUSCULAR DYSTROPHY?
Notify your pediatrician if the child exhibits the following conditions, possibly indicating muscular dystrophy:

• The infant lacks muscle tone or exhibits abnormal muscle weakness or difficulty breathing.

• The motor milestones (such as walking and running) are severely delayed.

• The calf muscles are abnormally enlarged.

WHAT CAUSES MUSCULAR DYSTROPHY?
The muscular dystrophies are caused by gene defects that cause the muscles to deteriorate. Researchers have found that Duchenne and Becker muscular dystrophies are caused by defects of a gene on the X chromosome that normally triggers production of the muscle protein dystrophin. The specific causes have not yet been identified in the other forms of muscular dystrophy.

HOW CAN THE PEDIATRICIAN TELL IF MY CHILD HAS MUSCULAR DYSTROPHY?
Unless there is a family history of the disease, the diagnostic process can be lengthy. The child may need various blood tests to measure enzymes released by muscle degeneration; tests of muscle function will be performed as well. A muscle biopsy, in which a small sample of muscle tissue is removed and examined microscopically, also may be performed.

WHAT TREATMENTS ARE AVAILABLE?
Current research suggests that transferring healthy genes into affected muscle may be beneficial. Because such treatment is still highly experimental, though, most therapy is aimed at relieving the child's symptoms and preventing complications; at present, there is no cure. The main treatment for the early stages of muscular dystrophy is regular physical therapy with passive stretching of key muscles and joint movement to reduce painful muscle contracture and possibly prolong walking. If joints become contracted, orthopedic surgery can provide some relief and improvement in function. Leg braces are helpful in prolonging independent standing and walking when muscles of the hips and legs have deteriorated to the point where the child cannot stand alone.

A child who can no longer walk must be equipped with a properly fitted wheelchair. Daily postural drainage is important to keep the lungs clear of accumulated fluids. If scoliosis sets in, two measures may help: an external shell-like body jacket designed to fit snugly around the trunk and reduce further curvature, and surgery to fuse the lower spinal column and relieve the curvature.

GETTING HELP
Call your doctor if:

• There is any history of muscular dystrophy in your or your partner's family. Ask about obtaining genetic counseling before starting your family.

• Your baby or child has poor muscle tone and delayed motor development.

Excerpt from THE DISNEY ENCYCLOPEDIA OF BABY & CHILD CARE, © 1995 DSH Communications, Inc. This material is based on current medical research and, to the best of the editors' knowledge and understanding, is accurate and valid. However the reader should not use information contained in this material to alter a medically prescribed regimen or as a form of self-treatment, without seeking the advice of a licensed physician.