3-Hydroxy-3-methylglutaric aciduria, combined with 3-methylglutaconic aciduria

1. A baby with severe metabolic acidosis was found to excrete abnormal amounts of 3-methylcrotonic acid, 3-methylglutaconic acid and 3-hydroxy-3-methylglutaric acid in urine. 2. Several other abnormal constitutents appear to be products of side-reactions and include 3-hydroxy-3-methylbutyric acid and 3-methylglutaric acid. 3. The profile of acids in urine indicates a blockage in the sixth step of leucine catabolism, the cleavage of 3-hydroxy-3-methylglutaryl-CoA to acetoacetic acid and acetyl-CoA.