Monday, October 12, 2009

Muscular Dystrophy

This is an essay I wrote for school last month, and thought I'd share it here.

Muscular Dystrophy is a hereditary condition consisting of the deterioration and weakening of the muscular system due to a mutation in one of the thousands of genes that program the proteins critical for muscle integrity. The muscles absorb additional calcium when the membrane that protects the muscles during contracting and relaxing are damaged, and the proteins leak. The additional calcium in the muscle tissue causes damage which leads to the death of the muscle fibers.

Penn State, Milton S. Hershey Medical Center (1) describes the nine most commonly classified forms of M.D. thus: Becker muscular dystrophy (BMD): Affects older boys and young men. Causes progressive muscle weakness, usually beginning in the legs. It is similar to Duchenne muscular dystrophy, but is generally milder. Congenital muscular dystrophy (CMD): A rare form present from birth. Symptoms usually progress slowly and include general weakness, flaccid tone, bent joints, and slow motor development. Fukuyama CMD is another type of congenital CMD that usually involves mental retardation, and is more common in Japan. Distal muscular dystrophy (DD): Symptoms begin in middle age or later. Causes weakness in the muscles of the feet and hands. Duchenne muscular dystrophy (DMD): The most severe form. Affects young boys. Causes progressive muscle weakness, usually beginning in the legs. Emery-Dreifuss muscular dystrophy (EDMD): Affects young boys. Causes muscle contractions in the calves; weakness in the calves, shoulders, and upper arms; and problems in the way electrical impulses travel through the heart to make it beat. Facioscapulohumeral muscular dystrophy (FSH): Also known as Landouzy-Dejerine disease. Begins in late childhood to early adulthood. Affects both males and females. Causes weakness in the muscles of the face, shoulders, and upper arms. May also affect the hips and legs. Limb-girdle muscular dystrophy (LGMD): Begins in late childhood to early adulthood. Affects males and females. Causes weakness in the muscles around the upper legs and shoulders. Myotonic dystrophy: Also known as Steinert's disease. Symptoms may begin any time from birth through adulthood. Affects males and females. Generalized weakness first occurs in the face, hands, and feet. People with this disease also have myotonia, the failure of the muscles to relax normally after use. Oculopharyngeal muscular dystrophy (OPMD): Affects adults of both sexes. Causes weakness in the eye muscles and throat.

Duchenne is the most severe form of MS, and can be deadly. Onset usually occurs in boys between 3 and 5 years old, and progresses rapidly. Often ambulation is no longer possible by adolescence, and respiration diminishes to the point of assistance as the teen years laps.

There is no cure for M.D., though there are numerous therapeutic and medical treatments that can help control the symptoms and progression. With the use of dietary changes, prescriptions such as Corticosteroids, and assistive devices, patients can be kept active as long as possible, which is very important, as the continual atrophying of the muscles is exacerbated by inactivity. Physical and occupational therapies can help counteract against weakness and contractures, however this becomes more difficult as fatigue sets in, and the muscles atrophy. The progression varies greatly from mild lifelong symptoms, severe onset at varying stages, and even death, depending on several factors including the type of Dystrophy.

Pre-pregnancy genetic screening is important, especially if there is a history of the condition in the family. Women can carry the genes that lead to MS without showing any symptoms, or developing the condition. Males only have one X chromosome, which is sufficient to cause the disorder. Women, having 2 X chromosomes, must have the mutation present in both for the condition to manifest, as the non mutated chromosome can over ride the mutated one.