title: Xanthurenic aciduria due to a mutation in KYNU encoding kynureninase.
abstract: Massive urinary excretion of xanthurenic acid, 3-hydroxykynurenine and kynurenine, known as xanthurenic aciduria or hydroxykynureninuria, in a young Somali boy suggested kynureninase deficiency. Mutation analysis of KYNU encoding kynureninase of the index case revealed homozygosity for a c.593 A > G substitution leading to a threonine-to-alanine (T198A) shift. A younger brother was found to have a similar excretion pattern and the same genotype. At present, neither of the two boys has symptoms of niacin deficiency. This is the first report linking xanthurenic aciduria to a mutation in the gene encoding kynureninase.
authors.affiliation: Department of Clinical Genetics, Rigshospitalet 4062, Blegdamsvej 9, DK-2100, Copenhagen, Denmark. mette.christensen@rh.regionh.dk
authors.forename: M
authors.initials: M
authors.lastname: Christensen
authors.forename: M
authors.initials: M
authors.lastname: Duno
authors.forename: A M
authors.initials: AM
authors.lastname: Lund
authors.forename: F
authors.initials: F
authors.lastname: Skovby
authors.forename: E
authors.initials: E
authors.lastname: Christensen
mesh_terms: D000225:Adenine; D000409:Alanine; D000592:Amino Acid Metabolism, Inborn Errors / Q000235:genetics*; D019943:Amino Acid Substitution; D002648:Child; D004252:DNA Mutational Analysis; D005838:Genotype; D006147:Guanine; D006720:Homozygote; D006801:Humans; D006867:Hydrolases / Q000172:deficiency / Q000235:genetics*; D008297:Male; D009154:Mutation; D010375:Pedigree; D013912:Threonine; D014977:Xanthurenates / Q000652:urine*
chemical_list: D014977:Xanthurenates; D013912:Threonine; C028330:xanthurenic acid; D006147:Guanine; D006867:Hydrolases; C021480:kynureninase; D000225:Adenine; D000409:Alanine