Ethnic variation in CYP2A6*7, CYP2A6*8 and CYP2A6*10 as assessed with a novel haplotyping method

Pharmacogenet Genomics. 2005 Mar;15(3):189-92. doi: 10.1097/01213011-200503000-00008.


Cytochrome P450 2A6 is the main human nicotine metabolizing enzyme coded for by a highly polymorphic gene, CYP2A6. CYP2A6*7, CYP2A6*8 and CYP2A6*10 are variant alleles common to Asian ethnicities. The CYP2A6*7 and CYP2A6*8 alleles each contain a non-synonymous single nucleotide polymorphism (SNP) 6558T>C and 6600G>T, respectively, whereas the CYP2A6*10 haplotype allele contains both. We have developed the first haplotyping assay; it can unambiguously distinguish the CYP2A6*7, CYP2A6*8 and CYP2A6*10 alleles. The allele frequencies of these three variants were assessed using the novel haplotyping assay in Chinese-Canadian (n=112), Chinese-American (n=221), Taiwanese (n=319), Korean-American (n=207) and Japanese-Canadian (n=64) populations, as well as in Caucasian (n=110) and African-Canadian (n=113) populations. Our new method demonstrated higher frequencies of CYP2A6*7 and CYP2A6*10, and a lower frequency of CYP2A6*8 in Asian populations, but no significant change of allele frequencies in Caucasian or African-Canadian populations.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Africa
  • African Continental Ancestry Group
  • Alleles
  • Aryl Hydrocarbon Hydroxylases / genetics*
  • Asian Continental Ancestry Group
  • Canada
  • China
  • Cytochrome P-450 CYP2A6
  • European Continental Ancestry Group
  • Exons
  • Gene Frequency
  • Genetic Variation
  • Genotype
  • Haplotypes*
  • Humans
  • Japan
  • Korea
  • Mixed Function Oxygenases / genetics*
  • Models, Genetic
  • Phenotype
  • Polymorphism, Single Nucleotide
  • Smoking
  • Taiwan
  • United States


  • Mixed Function Oxygenases
  • Aryl Hydrocarbon Hydroxylases
  • CYP2A6 protein, human
  • Cytochrome P-450 CYP2A6