The significance of the homozygous CYP2A6 deletion on nicotine metabolism: a new genotyping method of CYP2A6 using a single PCR-RFLP

Biochem Biophys Res Commun. 1999 Aug 19;262(1):146-51. doi: 10.1006/bbrc.1999.1182.


A convenient and specific CYP2A6 genotyping method was developed in this study. This method consisting of a single PCR-RFLP is capable of resolving the genotype into either CYP2A6*1 (wild type), CYP2A6*2, or CYP2A6*3. Among 252 Japanese persons genotyped, 241 were genotyped as the wild type, 1 as an unknown variant, and none as either CYP2A6*2 or CYP2A6*3. A homozygous deletion was found in the 10 remaining subjects. To clarify the metabolic significance of this deletion in the whole human body, urinary cotinine, the principal metabolite of nicotine, was analyzed subsequent to smoking. Cumulated urinary cotinine excretion in the homozygously CYP2A6-deleted individuals was about one-seventh compared to the control group (wild type). This study provides a firm experimental basis for correlating genotypic characterization of CYP2A6 with phenotypic expression of nicotine metabolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Aryl Hydrocarbon Hydroxylases*
  • Base Sequence
  • Cotinine / urine
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 Enzyme System / genetics*
  • DNA Primers / genetics
  • Exons / genetics
  • Female
  • Gene Frequency
  • Genetic Testing / methods*
  • Homozygote*
  • Humans
  • Japan
  • Male
  • Mixed Function Oxygenases / genetics*
  • Nicotine / metabolism*
  • Phenotype
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length*
  • Sensitivity and Specificity
  • Sequence Deletion / genetics*
  • Smoking / metabolism
  • Smoking / urine


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