The myopathies.

Extraordinary progress has been made in the recognition, understanding, and treatment of myopathy in the past several decades, aided by the application of molecular genetics, electrophysiology, muscle biopsy, and innovative therapies. The symptoms of muscle disease may vary among individual patients with acquired muscle disorders, as well as family members with inherited disorders. A careful history and examination is necessary to establish the symptoms, temporal progression, and distinctive areas of involvement, associated conditions, and suspected inheritance pattern in those patients in whom genetic cause is suspected. Selective laboratory testing is performed in symptomatic patients, which may include creatinine kinase level, electrodiagnostic studies, and, as warranted, examination of blood and muscle tissue for specific histopathological and genetic defects.