Systemic Carnitine Deficiency — A Treatable Inherited Lipid-Storage Disease Presenting as Reye's Syndrome

Abstract

A 3 1/2-year-old boy presented at three months of age with an acute episode of lethargy, somnolence, hypoglycemia, hepatomegaly, and cardiomegaly, which responded poorly to restoration of the blood sugar level to normal. The absence of ketonuria during subsequent episodes of severe hypoglycemia prompted a search for a defect in fatty acid oxidation. Plasma carnitine (2.0 to 5.0 μmol per liter), muscle carnitine (0.01 to 0.02 μmol per gram, wet weight) and liver carnitine (0.021 to 0.065 μmol per gram, wet weight) were all less than 5 per cent of the normal mean. During a 36-hour fast, ketones were barely detectable. Prolonged treatment with oral carnitine over a six-month period resulted in increased muscle strength, a dramatic reduction in cardiac size, relief of cardiomyopathy, partial repletion of carnitine levels in plasma and muscle, and complete repletion in the liver.