Muscular dystrophy refers to a group of genetic disorders that cause increased muscle weakness over time. The causes of muscular dystrophy vary depending on the specific type of the disease, but all are the result of a genetic mutation. In the most prevalent forms, such as Duchenne muscular dystrophy, a damaged X chromosome is inherited by a son from his mother. In other types of muscular dystrophy, either a son or daughter could inherit the damaged chromosome from one or both parents, though the disease can skip generations. There is no cure for the disease, but treatments are available to help slow its progression.
The most obvious symptoms of muscular dystrophy are usually muscle weakness and muscle deterioration, both of which result in physical disabilities. Scientists are not sure how exactly the muscle tissue is broken down. One of the possible causes of muscular dystrophy symptoms may be that the body is unable to produce certain proteins responsible for repairing muscle damage and maintaining muscle strength. If the proteins are not present, it may mean the body is not capable of repairing and protecting itself, and muscular dystrophy symptoms result.
Although all forms of the disease are a result of a deformed gene, specific causes of muscular dystrophy vary depending on the type. Duchenne muscular dystrophy, one of the most prevalent forms, is inherited by a son from his mother in a pattern called X-linked recessive inheritance. This means the mother passes a damaged X chromosome to her son.
Women who have only one defective X chromosome are known as carriers for the disease. They may have symptoms including muscle weakness and heart problem, or they may not experience any health problems. Sometimes, the mutation is not inherited but develops on its own.
The causes of muscular dystrophy in its other forms and the related patterns of genetic inheritance are sometimes the same as in Duchenne, but they can be different. Some types can be inherited by a child from one or both parents. Others, such as myotonic dystrophy and similar types, can affect male or female children equally. If either parent has the defective gene, there is a 50 percent chance that the child will develop the disease. Still other forms of muscular dystrophy can only be passed down if both parents carry the defective gene.
