Hartnup Disease

Medical Condition:
Hartnup Disease

A disorder of amino acid transport characterized by the childhood (or rarely adult) onset of photosensitive dermatitis and intermittent neurologic symptoms. Ataxia, personality changes, migraine headaches, and photophobia may occur periodically. The disorder results from impaired sodium-dependent transport of neutral amino acids across the brush border membrane of the small intestine and renal tubular epithelium. (From Menkes, Textbook of Child Neurology, 5th ed, pp59-60)