Muscular dystrophy

 It  is a genetic disease passed from one generation to the next in an X-linked recessive fashion. This means that females carry the defective gene that causes the disorder, but males almost exclusively are affected by the disease. When a mother carries the defective gene, her female children each have a 50 percent chance of carrying the gene also, but they, too, will not show any symptoms. However, each male child has a 50 percent chance of having the disease and showing signs of the disorder. Although the disease is present from conception, symptoms do not usually develop until the child is 5 or 6 years old, or perhaps even a year or two later. When one child in the family has already developed the disease, the parents are more able to recognize early signs, and a second son may be identified as being affected when he is 3 or 4 years old.

In recent years, scientists funded by the Muscular Dystrophy Association have identified the gene containing defects that cause Duchenne dystrophy, as well as a milder form of the disorder known as Becker muscular dystrophy. This has helped greatly in definitively establishing the diagnosis in boys with the disease, and in being able to tell female relatives whether or not they are carriers, and thus likely to pass the disease on to their offspring.

• We will first describe the natural course of the disease. The symptoms result from weakness of the muscles.
• First, a boy affected with Duchenne muscular dystrophy will have some difficulty in keeping up with other children when running. He’ll develop a characteristic “waddling” run (as he becomes weaker) that will also be present when he walks. He’ll have difficulty going up steps, and have to first put one foot, then the other foot, on the same step before moving on to the next one.
• Soon he’ll have to pull himself up using the handrail.