<prompt> Tryptophan deficiency leads to:Hers diseaseLesch Nyhan syndromeHartnup diseaseAlkaptonuria  <response>: 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. Hers disease choice A is caused by deficiency of liver phosphorylase. 