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Published on: April 1, 2019

The CYP2A subfamily: function, expression and genetic polymorphism

H Raunio1, A Rautio, O Pelkonen

  • 1Department of Pharmacology and Toxicology, University of Oulu, Finland.

IARC Scientific Publications
|September 24, 1999
PubMed

Insights

The CYP2A6 gene encodes an enzyme crucial for metabolizing toxins like tobacco smoke and pharmaceuticals. Genetic variations in CYP2A6 can lead to poor metabolizer phenotypes, impacting toxin processing and disease risk.

Area of Science:

  • Pharmacogenomics
  • Enzyme kinetics
  • Toxicology

Background:

  • The CYP2A6 gene is part of the human CYP2A subfamily, alongside CYP2A7 and CYP2A13.
  • CYP2A6 enzyme is primarily expressed in the liver and metabolizes clinically significant compounds, including pharmaceuticals, procarcinogens, and tobacco smoke constituents.
  • Coumarin serves as a high-affinity substrate for CYP2A6, enabling its use in phenotyping tests.

Purpose of the Study:

  • To review the current understanding of the CYP2A6 gene and its enzyme.
  • To highlight the significance of CYP2A6 in metabolizing various xenobiotics.
  • To underscore the need for further research into CYP2A6 polymorphism and its association with diseases.

Main Methods:

  • Literature review of studies on CYP2A6 gene and enzyme.
  • Analysis of coumarin 7-hydroxylation as a phenotyping test.
  • Examination of known CYP2A6 mutant alleles (CYP2A6*2, CYP2A6*3) and their association with poor metabolizer phenotypes.

Main Results:

  • Two mutant alleles, CYP2A6*2 and CYP2A6*3, have been identified.
  • Homozygosity for these mutations results in a poor metabolizer (PM) phenotype, characterized by impaired coumarin 7-hydroxylation.
  • Limited information exists regarding CYP2A6 inducibility and regulation, though mouse orthologue studies suggest novel induction pathways.

Conclusions:

  • CYP2A6 genetic polymorphism is a recent discovery with unknown associations with diseases or adverse outcomes.
  • Further studies are warranted to explore the link between variant CYP2A6 alleles and health outcomes, given the enzyme's role in metabolizing numerous toxins.
  • Understanding CYP2A6 variations is critical for personalized medicine and assessing risks associated with environmental exposures.

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