<prompt> Hartnups disease is associated with disturbed metabolism ofPhenylalaineTyrosineTryptophanValine  <response>: C Tryptophan HARTNUP DISEASE: This disorder is characterized by reduced intestinal absorption renal reabsorption of neutral amino acids. The defect involves an amino acid transporter on the brush border of the jejunum the proximal tubule. Intestinal absorption of free amino acids is reduced, though the neutral amino acids can be absorbed when present in di- tripeptides. Degradation of unabsorbed tryptophan by intestinal bacteria produces indolic acids that are absorbed subsequently excreled at high levels in the urine of these patients. The disorder is inherited as an autosomal recessive trait with an estimated incidence of 1 in 24,000 live births. Linkage analysis suggests a locus on chromosome 5. 