Which of the following is caused by defective transpo of tryptophan?

Hanup disease It is an inherited disorder in the metabolism of tryptophan. It is due to defective transpo of tryptophan and other neutral amino acids in the intestine and kidney. This results in deficiency of tryptophan leading to decreased synthesis of niacin and serotonin. Thus there are pellagra (niacin deficiency), neurological symptoms (serotonin deficiency) and amino aciduria due to defective transpo of amino acids in kidney.