What is the syndrome of CPT deficiency?
CPT II deficiency is an autosomal recessive disorder characterized by attacks of exertional myalgias and myoglobinuria (80%). Patients, most of whom are men, experience no difficulty with short bursts of strenuous activity. Indeed, the favorite recreational sport of the patient is often weight lifting. When prolonged exercise is demanded, particularly in the fasting state (when the body is dependent on fatty acid metabolism as a source of energy), muscle pain, fatigue, and myoglobinuria may occur. Patients do not experience the “second wind phenomenon.” CPT II deficiency is the most common genetic metabolic myopathy causing recurrent rhabdomyolysis. The resultant myoglobinuria can cause renal failure. Diagnosis is made by genetic testing or measuring CPT activity in biopsied muscle. Treatment consists of education about avoidance of prolonged strenuous exercise and fasting. Carbohydrates before and during exercise and a high carbohydrate diet may improve exercise tolerance.
