Familial hypertryptophanemia, tryptophanuria and indoleketonuria

Two patients presenting with mental subnormality and severe emotional lability were examined for possible inborn errors of metabolism. Amino acid and organic acid analyses of their plasma and urine revealed a novel and grossly abnormal metabolism of tryptophan. Basal levels of plasma tryptophan were ten times that of controls and the 24-hour urinary excretion of tryptophan was up to 50 times greater than normal. Both patients excreted about 100 times the normal amounts of indoleacetic, indolelactic and indolepyruvic acids. Administration of oral Antibiotic to one of the patients to eliminate intestinal bacteria did not result in any reduction in the excretion of the indoleic acids. The results are interpreted in terms of a possible congenital defect in the normal conversion of tryptophan to kynurenine.