Aliphatic C6−C14 dicarboxylic acids in urine from an infant with fatal congenital lactic acidosis

A newborn male infant with a severe metabolic acidosis who died one day after birth was found to have high levels of lactic acid in his urine, together with a series of dicarboxylic acids with 6 to 14 carbon atoms chain length. Adipic and suberic acids which occurred in a concentration of ~ 0.05 mmoles/1 were also present in the urine of normal newborns. The concentration in the urine of dicarboxylic acids with 10, 12 and 14 carbon atoms was 0.1, 0.5 and 0.2 mmoles/1. These acids were saturated, monoenic and dienic. The monounsaturated acids were mainly of the cis-Δ₅ configuration. It is suggested that the findings could be consistent with a defect in the normal β-oxidation of fatty acids located at the acyl-CoA dehydrogenase step.