ABSTRACT
The muscular dystrophies are a diverse group of inherited muscle disorders characterized by progressive muscle weakness and wasting with characteristic histologic abnormalities such as degeneration, necrosis, and regeneration of muscle fibers. With progress in molecular genetics methods, new discoveries of dystrophin and related molecules have dramatically changed the understanding and diagnosis of a large group of muscular dystrophy patients. Dystrophin and its related molecular associates are tightly associated and form an essential cytoskeletal system (dystrophin-glycoprotein complex) at the muscle fiber surface membrane, which is critical for maintaining the integrity of the sarcolemma and muscle fibers. Deficiency of one of these sarcolemmal proteins, including dystrophin, dystroglycans, sarcoglycans, and laminin-2, leads to the breakdown and instability of muscle fibers and to clinically observed progressive muscle weakness. Identification of the molecular cause of muscular dystrophies would allow a genetic oriented classification and diagnosis using DNA or protein analysis. However, definition of the molecular pathogenesis of muscular dystrophies has not been completely possible until now. Future advances in this field should allow the exact diagnosis and treatment of muscular dystrophies.