描述
Hartunup Disorder (HND, Hartnup Disease) is an autosomal recessive disease caused by a mutation in the SLC6A19 which codes for sodium-dependent neutral amino acid transporter B(0). A deficiency in this enzyme results in accumulation of L-alanine, L-asparagine, L-histidine, indoleacetic acid, L-isoleucine, L-leucine, L-phenylalanine, L-serine, L-threonine, L-tryptophan, L-valine, and L-tyrosine in urine. Symptoms include pellagra, psychosis, ataxia, and mental retardation. Treatment includes nicotinamide.