Which of the following is caused by defective transport of tryptophan -

Ans. is 'a' i.e., Hartnup disease Hartnup diseaseo It is an inherited disorder in the metabolism of tryptophan.o It is due to defective transport of tryptophan and other neutral amino acids in the intestine and kidney,o This results in deficiency of tryptophan leading to decreased synthesis of niacin and serotonin,o Thus there are pellagra (niacin deficiencyj, neurological symptoms (serotonin deficiency) and amino aciduria due to defective transport of amino acids in kidney.