A case of McArdle's syndrome with a positive family history

Abstract

The case histories of a 51-year-old man and his 44 year-old sister are presented in association with McArdle''s syndrome which involves an inability to maintain exercise because muscle pain and stiffness develop during the process. Observations during exercise showed that both the forearm and leg muscles were abnormal. The pain experienced in the patient''s legs on exercise with adequate circulation was of the same deep, diffuse, severe type felt on exercising an ischemic limb, but slower in onset. No greater swelling occurred in the muscles of the patient than in a control subject and the patient did not show the increased blood glucose, lactate, and pyruvate levels found in the control. Electromyography revealed abnormal muscle activity after strenuous work but no abnormalities in muscle at rest or when weakly contracted. Studies of a muscle biopsy from the left deltoid of the patient showed granular necrosis and vacuolar degeneration of fibers. Glycogen content increased and phosphorylase activity decreased. Symptoms are alleviated by injections of glucose or fructose but the effect is not prolonged. In view of familiar involvement inheritance by an autosomal recessive gene is most likely.