hartnup disease

Hartnup disease (also known as 'pellagra-like dermatosis' and 'Hartnup disorder') is an autosomal recessive metabolic disorder affecting the absorption of nonpolar amino acids (particularly tryptophan that can be, in turn, converted into serotonin, melatonin, and niacin). Niacin is a precursor to nicotinamide, a necessary component of NAD+.The causative gene, SLC6A19, is located on chromosome 5. It is named after the English family, Hartnup, who suffered from this disease.

Hartnup disease manifests ...