Walsh & Hoyt: Muscular Dystrophies

The term ""muscular dystrophy"" covers a group of genetically determined disorders that cause progressive weakness and wasting of the skeletal muscles and that are assumed to affect the muscle cell directly. Some forms cause death after 1520 years, whereas others are compatible with a normal life expectancy. The distinction between the terms ""myopathy"" and ""dystrophy"" breaks down, however, when it is realized that some glycogenolytic myopathies, like acid maltase deficiency, can progress inexorably like dystrophies, and some dystrophies, like Becker dystrophy, may hardly progress at all. Nevertheless, the diagnostic category is a tradition. Although the diagnosis of this group of disorders cannot be established by morphology alone, histologic examination of an affected muscle can exclude other myopathies (e.g., the congenital myopathies and the mitochondrial myopathies). In others, molecular genetic testing can provide the correct diagnosis.