Hartnup Disease causes
Overview
Hartnup disease (also known as "pellagra-like dermatosis"[1] and "Hartnup disorder"[2]) is an autosomal recessive[3] 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+.[4]:541
The causative gene, SLC6A19, is located on chromosome 5.[5]
Causes
Hartnup disease is inherited as an autosomal recessive trait. Heterozygotes are normal. Consanguinity is common. The failure of amino-acid transport was reported in 1960 from the increased presence of indoles (bacterial metabolites of tryptophan) and tryptophan in the urine of patients as part of a generalized aminoaciduria of the disease. The excessive loss of tryptophan from malabsorption was the cause of the pellagra like symptoms. From studies on ingestion of tryptophan it seemed that there was a generalized problem with amino-acid transport.[6] In 2004, a causative gene, SLC6A19, was located on band 5p15.33. SLC6A19 is a sodium-dependent and chloride-independent neutral amino acid transporter, expressed predominately in the kidneys and intestine.[7]
References
- ↑ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0.
- ↑ Online Mendelian Inheritance in Man (OMIM) 234500
- ↑ Kleta R, Romeo E, Ristic Z, Ohura T, Stuart C, Arcos-Burgos M, Dave MH, Wagner CA, Camargo SR, Inoue S, Matsuura N, Helip-Wooley A, Bockenhauer D, Warth R, Bernardini I, Visser G, Eggermann T, Lee P, Chairoungdua A, Jutabha P, Babu E, Nilwarangkoon S, Anzai N, Kanai Y, Verrey F, Gahl WA, Koizumi A (September 2004). "Mutations in SLC6A19, encoding B0AT1, cause Hartnup disorder". Nature Genetics. 36 (9): 999–1002. doi:10.1038/ng1405. PMID 15286787.
- ↑ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
- ↑ Seow HF, Brer S, Brer A, Bailey CG, Potter SJ, Cavanaugh JA, Rasko JE (September 2004). "Hartnup disorder is caused by mutations in the gene encoding the neutral amino acid transporter SLC6A19". Nature Genetics. 36 (9): 1003–7. doi:10.1038/ng1406. PMID 15286788.
- ↑ Milne, M.D., Crawford, M.A., Girao, C.B. and Loughridge, L. (1961) The metabolic disorder of the Hartnup disease. Q. J. Med. 29: 407-421
- ↑ Lidija Kandolf Sekulovic. "Hartnup Disease". Retrieved 2008-11-23.