Biochemical and physiologic consequences of carnitine palmityltransferase deficiency.
A patient with a long history of exercise-unduced pain developed myoglobinuria and respiratory failure following extensive exercise (football). Although muscle histochemistry was normal, tissue oxidation of 14C-labeled palmitate was decreased, and muscle carnitine palmityltransferase (CPT) activity was one-tenth of normal. During fasting, his creatine kinase (CK) rose from 127 mu/ml to 278 mu/ml and blood ketones failed to exhibit a normal rise. Triglycerides were normal, as was fatty-acid mobilization. Prolonged exercise resulted in an inordinately increased CK with only moderate elevations in lactate. Treatment with medium-chain triglycerides did not alter his symptoms or improve exercise performance. Pain on exercise is a common complaint, but the occurrence of myoglobinuria points to a defect of energy metabolism; Screening for defects of fat utilization may be accomplished by the prolonged-exercise test, invitro oxidation of 14C-labeled substrates, and prolonged fasting.
D000217:Acyltransferases / Q000172:deficiency*; D000328:Adult; D002334:Carnitine O-Palmitoyltransferase / Q000172:deficiency*; D003402:Creatine Kinase / Q000097:blood; D004734:Energy Metabolism; D005215:Fasting; D005227:Fatty Acids / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D007659:Ketones / Q000097:blood; D008297:Male; D009132:Muscles / Q000378:metabolism; D009212:Myoglobinuria / Q000209:etiology*; D010101:Oxygen Consumption; D010146:Pain; D005082:Physical Exertion; D012131:Respiratory Insufficiency / Q000209:etiology*; D013577:Syndrome
D005227:Fatty Acids; D007659:Ketones; D000217:Acyltransferases; D002334:Carnitine O-Palmitoyltransferase; D003402:Creatine Kinase