For information about these and other types of nerve and muscle disorders, see A Synopsis of Disorders or contact the Muscular Dystrophy Association in your State. The primary cause is the genetic defect. In the Duchenne and Becker types, the defect is in the gene which enables the muscle fibres to make dystrophin. The muscle fibres in Duchenne and Becker dystrophies are deficient in dystrophin, more severely so in the Duchenne type than in the Becker type. Abnormal genes responsible for Myotonic Dystrophy and many cases of Facioscapulohumeral MD have also been identified and the mechanisms by which the abnormal genes cause muscle weakness are beginning to be understood.
Work is ongoing to try to cover the genetic basis of the other MD's.
There is as yet no cure for any of the MD's. Medical management, ideally at special clinics for muscle diseases, includes physiotherapy and a variety of other professional activities directed at maximising the independence, physical capabilities, general health and quality of life of affected people. These efforts, although not curative, are effective. They do contribute in some degree to the achievements of people with MD, which are so often a source of inspiration to others. To amount of research devoted to the MD's across the world is enormous.