Canadian Native Indians exhibit unique CYP2A6 and CYP2C19 mutant allele frequencies

Clin Pharmacol Ther. 1998 Oct;64(4):378-83. doi: 10.1016/S0009-9236(98)90068-6.


Many human cytochromes P450 (CYP) enzymes are polymorphically expressed, resulting in interindividual and interethnic differences in the metabolism of substrate drugs. Little is known about the genetic variation of CYP enzymes in Canadian Native Indians. We therefore determined the CYP2C19 and CYP2A6 mutant allele frequencies in 159 Canadian Native Indians and compared them with white and Asian subjects. Canadian Native Indians differed significantly from both white and Asian populations in allelic patterns of both CYP2C19 (19.1% CYP2C19*2 and 0% CYP2C19*3) and CYP2A6 (0.9% CYP2A6*2 and 13.9% CYP2A6*3). In addition, analysis of the Canadian Native Indian data suggested that there may be an association between the presence of the CYP2C19 and CYP2A6 mutant alleles such that the co-occurrence of these 2 alleles is higher than would be predicted on the basis of their individual frequencies in this population.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles*
  • Aryl Hydrocarbon Hydroxylases*
  • Asian Continental Ancestry Group / genetics
  • Canada
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 CYP2C19
  • Cytochrome P-450 Enzyme System / genetics*
  • European Continental Ancestry Group / genetics
  • Female
  • Genotype
  • Humans
  • Indians, North American / genetics*
  • Male
  • Mixed Function Oxygenases / genetics*
  • Mutation*


  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • Aryl Hydrocarbon Hydroxylases
  • CYP2A6 protein, human
  • CYP2C19 protein, human
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 CYP2C19