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Duchenne and Becker’s muscular dystrophies are disorders which result in muscle weakness, nearby the torso. The gene abnormality that results in Duchenne’s muscular dystrophy is different from the gene defect that results in Becker muscular dystrophy, but both abnormalities involve the same gene. The genes are recessive and are carrid on the x chromosome. While a woman may carry the abnormal gene, she does not have the disorder because the normal x chromosome is compensating for the gene abnormality on the other x-chromosome. However, any man who receives abnormal x chromosome will have the disorder. Boys with duchenne muscular dystrophy have almost total deficiency of dystrophin – an essential protein in the muscle, which is important for keeping the structures of the muscle cells under control. Of every 100,000 born boys, 20 to 30 get this dystrophy. Boys, who have Becker muscular dystrophy produce dystrophin (protein), but the dystrophin is oversized and does not work properly. Of every 100,000 boys born, 3 have Becker muscular dystrophy. Duchenne muscular dystrophy commonly first appears in boys between ages of three and seven as a weakness around or in the pelvis. Shoulder muscle weakness usually follows and gets steadily worse. As the muscle weakens, it also enlarges, but the defected tissue of the muscle is not strong. In 90% of the boys, who have duchenne muscular dystrophies, the muscle of the heart also weakens and enlarges, resulting in problems with heartbeats, which may be seen on an EKG (electrocardiogram). Boys who have duchenne muscular dystrophies usually waddle, fall frequently, have difficulties standing up from sitting positions, and have trouble climbing stairs. The muscles of their legs and arms generally contract around the joint so that the knee and elbow cannot completely extend. In some cases, the scoliosis (abnormally curved spine) progresses. B age ten or twelve, most children with duchenne muscular dystrophy are confined to a wheelchair. The increased weakness also makes the children prone to pneumonia and other diseases, and most of them die by age 20. On other hand, boys, who have Becker muscular dystrophies have less severe symptoms. Symptoms first occur at approx. age 10. At age 16, very few are confined to wheelchairs, and about 90% survive by at least age 20. A physician suggests muscular dystrophies when young boys become weak and grow weak. Creatinine kinase (enzyme) leaks out of muscle cells, resulting in enzyme amounts in the blood to be too high. However, creatinine kinase high levels do not mean that an individual has muscular dystrophy; other disorders of muscle can also result in increased amount of this enzyme. A physician commonly obtains a muscle biopsy to determine the diagnosis. Under the microscope, the muscle usually shows abnormally large fibers of muscle and dead tissue. In the late stages, fat, and other tissue replaces the dead tissue of the muscle. A doctor diagnoses Suchenne muscular dystrophy by performing specific tests showing extremely low amounts of dystrophin (protein) in the muscles. Tests to confirm the diagnosis such as electromyography (study of muscle functions) and nerve conduction study are performed. No cure is available for Beckers or Duchenne’s muscular dystrophies as of today. Exercises and physical therapy may help protect the muscle from contracting around the joints. In some cases, surgery is required to release painful, tight muscles. Corticosteroids, such as Prednisone may relieve weakness of the muscle for a while. Families with members with Becker or Duchenne’s muscular dystrophies are asked to consult with genetic counselors.
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