Genetic variations of the AHR gene encoding aryl hydrocarbon receptor in a Japanese population.

Aryl hydrocarbon receptor (AhR), encoded by the AHR gene, is a transcriptional factor that induces various drug metabolizing enzymes in response to diverse endogenous and exogenous ligands. In order to identify genetic variations of the AHR gene, genomic DNA from 242 Japanese individuals was sequenced. We identified 32 single nucleotide variations, including 25 novel ones [7 were in the coding exons, 7 in the introns, 1 in the 5'-untranslated region (UTR), 5 in the 3'-UTR, 2 in the 5'-flanking region, and 3 in the 3'-flanking region] and a GGGGC repeat polymorphism (a novel microsatellite marker) in the promoter region. The novel nonsynonymous variations were 50A>C (Lys17Thr), 1202A>G (Lys401Arg), 1459A>G (Asn487Asp), and 1541T>C (Ile514Thr). The allele frequencies were 0.010 for 1459A>G (Asn487Asp) and 0.002 for the other 3 variations. Also detected in this analysis was the known nonsynonymous single nucleotide polymorphism 1661G>A (Arg554Lys) at a 0.444 frequency.