title: Limitation of cigarette consumption by CYP2A6*4, *7 and *9 polymorphisms.
abstract: The whole gene deletion CYP2A6*4, the defect of the main nicotine oxidase, contributes to limiting lifelong and daily cigarette consumption. However, the effects on smoking habits of CYP2A6*7 and *9, two major functional polymorphisms common in Asian populations, have not been reported. The present study examined the relationship between polymorphisms *4, *7 and *9 with the smoking habits of 200 Japanese smokers who visited the Keio University Hospital (Tokyo, Japan). The allele frequencies of *1 (wild type), *4, *7 and *9 were 52, 17, 11 and 20%, respectively. When the three polymorphisms were considered simultaneously, the percentages of homozygous wild type, heterozygote, and homozygous mutants and compound heterozygotes were 26.0, 52.5 and 21.5%, respectively. Homozygous mutants and compound heterozygotes (n = 43) smoked fewer cigarettes daily than heterozygotes (n = 105) and homozygous wild-type individuals (n = 52). Smokers with *7/*7, *9/*9 or *7/*9 had lower daily cigarette consumption than smokers with *1/*1. In conclusion, polymorphisms *4, *7 and *9 of CYP2A6 were detected in approximately three out of four Japanese smokers, and their daily cigarette consumption was genetically modulated by these functional polymorphisms.
authors.affiliation: Division of Pulmonary Medicine, Dept of Medicine, Keio University, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Minematsu
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Furuuchi
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Tateno
authors.forename: A
authors.initials: A
authors.lastname: Ishizaka
mesh_terms: D000368:Aged; D000483:Alleles; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D065637:Cytochrome P-450 CYP2A6; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000235:genetics*; D011110:Polymorphism, Genetic; D012907:Smoking / Q000453:epidemiology / Q000235:genetics*; D018709:Statistics, Nonparametric
chemical_list: D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6