Hydroxymethylglutaryl CoA lyase deficiency: features resembling Reye syndrome.

A 2-year-old boy had acute fever, malaise, and somnolence with hepatomegaly, increased blood ammonia content (338 microM), high SGOT, low blood glucose content, and mild acidosis. A liver biopsy showed diffuse accumulation of lipid droplets in swollen hepatocytes, and abnormal urinary metabolites included beta-hydroxy-beta-methyl glutarate (HMG), beta-methylglutaconate, beta-hydroxyisovalerate, and beta-methylglutaric and glutaric acids. In cultured skin fibroblasts and liver, beta-hydroxy-beta-methyl glutaryl CoA lyase activity was about 10% of normal. Therefore, a genetic deficiency of HMGCoA lyase activity can cause a clinical syndrome similar to that of Reye syndrome when the patient is stressed by an acute viral infection.