Dystrophin: a clinical perspective.

Dystrophin, the protein product of the gene related to Duchenne and Becker muscular dystrophies, is a large cytoskeletal protein associated with the muscle fiber membrane. Recently identified dystrophin-related myopathies affecting animals can serve as experimental models for human disease. Immunologic detection of dystrophin in clinical muscle biopsies provides a direct biochemical test for both Duchenne and Becker muscular dystrophies. Applications of dystrophin testing include improved diagnostic accuracy, carrier detection, fetal diagnosis, and evaluation of asymptomatic male infants identified as a result of neonatal screening for increased serum creatine kinase levels. Identification of dystrophin has brought us to the point of addressing rational therapies.