title: Limited frequency of the CYP2C19*17 allele and its minor role in a Japanese population.
abstract: BACKGROUND
  A novel CYP2C19 gene variant, CYP2C19*17, is associated with increased metabolic activity. Ethnic differences in the frequency of the variant allele have been reported. However, the frequency of the CYP2C19*17 allele has not been studied in the Japanese population.
  
  
  CONCLUSIONS
  In a population of 265 healthy Japanese subjects, a low frequency (1.3%) of the CYP2C19*17 allele was observed. The limited frequency of the *17 allele and the absence of a subject homozygous for *17 indicated that CYP2C19*17 would play a minor role in a Japanese population.
  
  
  OBJECTIVE
  We investigated the CYP2C19*17 allelic frequency in Japanese subjects, and evaluated whether CYP2C19*17 is an important determinant of interindividual variability of CYP2C19 activity.
  
  
  METHODS
  We enrolled 265 subjects to determine their CYP2C19 genotype and plasma metabolic ratio following a single dose of 40 mg omeprazole.
  
  
  RESULTS
  Seven subjects heterozygous for CYP2C19*17 and no *17/*17 subjects resulted in the CYP2C19*17 frequency being 1.3%. These heterozygotes had moderate metabolic activities when compared with the metabolic ratio of the other subjects.
  
  
  CONCLUSIONS
  The low frequency of CYP2C19*17 and the absence of *17/*17 indicates that CYP2C19*17 plays a minor role in the Japanese population.
authors.affiliation: Department of Clinical Pharmacology, Hirosaki University School of Medicine, Hirosaki, Aomori 036-8562, Japan.
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Uno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Tomonori
authors.initials: T
authors.lastname: Tateishi
mesh_terms: D000328:Adult; D000483:Alleles; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D065731:Cytochrome P-450 CYP2C19; D005260:Female; D005787:Gene Frequency / Q000235:genetics*; D006801:Humans; D008297:Male; D006899:Mixed Function Oxygenases / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics
chemical_list: D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19