Tryptophan deficiency leads to:

(C) Hartnup disease # Hartnup disease occurs due to impaired intestinal absorption and renal re-absorption of a neutral amino acid, tryptophan.> Tryptophan is required for synthesis of serotonin and nicotinic acid.> Neurological manifestations of Hartnup disease are due to decreased synthesis of serotonin while pellagra-like rash occurs due to decreased synthesis of nicotinic acid.> Her's disease (choice A) is caused by deficiency of liver phosphorylase.