Characterisation and PCR-based detection of a CYP2A6 gene deletion found at a high frequency in a Chinese population

FEBS Lett. 1999 Apr 1;448(1):105-10. doi: 10.1016/s0014-5793(99)00359-2.


Cytochrome P450 2A6 is an important human hepatic P450 which activates pre-carcinogens, oxidises some drugs and constitutes the major nicotine C-oxidase. In fact, results have been presented in the literature which suggested a relationship between the distribution of defective CYP2A6 alleles and smoking behaviour as well as cigarette consumption. In the present report, we describe the structure of a novel CYP2A locus where the whole CYP2A6 gene has been deleted, resulting in an abolished cytochrome P450 2A6-dependent metabolism. The origin of this locus is apparently due to an unequal crossover event between the 3'-flanking region of the CYP2A6 and CYP2A7 genes. A rapid PCR-based method for the detection of the CYP2A6del allele was developed and the allele frequency was 15.1% among 96 Chinese subjects, but only 1.0% in Finns (n=100) and 0.5% in Spaniards (n=100). In the Chinese population, we did not detect any CYP2A6*2 alleles using an improved genotyping procedure, in contrast to the 11-20% previously reported. It is concluded that genotyping for the CYP2A6del allele is of great importance in studies correlating, for example, smoking behaviour, pre-carcinogen activation or drug metabolism to the CYP2A6 genotype, in particular when oriental populations are investigated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Aryl Hydrocarbon Hydroxylases*
  • Asian People / genetics*
  • Base Sequence
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 Enzyme System / genetics*
  • DNA, Complementary
  • Finland
  • Gene Deletion*
  • Gene Frequency
  • Genotype
  • Humans
  • Mixed Function Oxygenases / genetics*
  • Molecular Sequence Data
  • Phenotype
  • Polymerase Chain Reaction / methods*


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