Skip to main content
Log in

Flow Cytometric Assay for Genotyping Cytochrome P450 2C9 and 2C19

Comparison with a Microelectronic DNA Array

  • Original Research Article
  • Published:
American Journal of Pharmacogenomics

Abstract

Introduction: Cytochrome P450 (CYP) 2C9 and 2C19 metabolize a wide range of therapeutically important drugs. Genetic polymorphisms in the CYP2C9 and CYP2C19 genes result in variations in drug response. To correlate the dose required for therapeutic drug efficacy with genotype, accurate and reliable methods for detecting single nucleotide polymorphisms (SNPs) of CYP2C9 and CYP2C19 are required.

Study design: We evaluated two technologies for genotyping CYP2C9 (*2 and *3 alleles) and CYP2C19 (*2 and *3 alleles). We developed a multiplexed flow cytometric assay based on the Luminex xMAP™ system and oligonucleotide-tagged Universal Array™ microspheres. The Luminex assay was compared with the eSensor™ DNA detection system, provided by Motorola Life Sciences. Genotypes determined by the two methods were confirmed by sequence analysis.

Results: Of the 101 whole-genome amplified DNA samples genotyped by the Luminex method, 15 (14.8%) were heterozygous and 1 was homozygous for the CYP2C9*2 polymorphism. For the CYP2C9*3 polymorphism, 13 (12.9%) were heterozygous and 1 was homozygous. Two samples had the CYP2C9*2/*3 genotype. For CYP2C19*2, 17 (16.8%) of the samples were heterozygous and one was homozygous. The CYP2C19*3 polymorphism was not found. Genotypes determined by the Luminex assay were in complete concordance with the eSensor™ SNP assay results. A dilution study showed that 1.5ng of nucleic acid was adequate for PCR and subsequent detection of SNPs by the Luminex assay. The within run and between run coefficients of variance (CVs) for allelic ratios determined by the Luminex procedure were found to be ≤4.1% and ≤9.1%, respectively, for the alleles present.

Conclusion: Both the in-house Luminex method and the eSensor™ DNA detection system reproducibly and unambiguously genotyped SNPs of CYP2C9 and CYP2C19 in the samples tested.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Table I
Fig. 1
Fig. 2
Table II
Fig. 3

Similar content being viewed by others

References

  1. Rendic S. Summary of information on human CYP enzymes: human P450 metabolism data. Drug Metab Rev 2002; 34: 83–448

    Article  PubMed  CAS  Google Scholar 

  2. Oscarson M, Ingelman-Sundberg M, Daly AK, et al. Human cytochrome P450 (CYP) alleles [online]. Available from URL: http://www.imm.ki.se/CYPalleles [Accessed 2003 Aug 31]

  3. Weinshilboum R. Inheritance and drug response. N Engl J Med 2003; 348: 529–37

    Article  PubMed  Google Scholar 

  4. Goldstein JA. Clinical relevance of genetic polymorphisms in the human CYP2C subfamily. Br J Clin Pharmacol 2001; 52: 349–55

    Article  PubMed  CAS  Google Scholar 

  5. Wrighton SA, Stevens JC, Becker GW, et al. Isolation and characterization of human liver cytochrome P450 2C19: correlation between 2C19 and S-mephenytoin 4′-hydroxylation. Arch Biochem Biophys 1993; 306: 240–5

    Article  PubMed  CAS  Google Scholar 

  6. Wedlund PJ. The CYP2C19 enzyme polymorphism. Pharmacology 2000; 61: 174–83

    Article  PubMed  CAS  Google Scholar 

  7. Desta Z, Zhao X, Shin J-G, et al. Clinical significance of the cytochrome P450 2C19 genetic polymorphism. Clin Pharmacokinet 2002; 41: 913–58

    Article  PubMed  CAS  Google Scholar 

  8. de Morais SM, Wilkinson GR, Blaisdell J, et al. The major genetic defect responsible for the polymorphism of S-mephenytoin metabolism in humans. J Biol Chem 1994; 269: 15419–22

    PubMed  Google Scholar 

  9. Ibeanu GC, Goldstein JA, Meyer U, et al. Identification of new human CYP2C19 alleles (CYP2C19*6 and CYP2C19*2B) in a Caucasian poor metabolizer of mephenytoin. J Pharmacol Exp Ther 1998; 286: 1490–5

    PubMed  CAS  Google Scholar 

  10. Xie HG, Prasad HC, Kim RB, et al. CYP2C9 allelic variants: ethnic distribution and functional significance. Adv Drug Deliv Rev 2002; 54: 1257–70

    Article  PubMed  CAS  Google Scholar 

  11. Lee CR, Goldstein JA, Pieper JA. Cytochrome P450 2C9 polymorphisms: a comprehensive review of the in-vitro and human data. Pharmacogenetics 2002; 12: 251–63

    Article  PubMed  CAS  Google Scholar 

  12. Taube J, Halsall D, Baglin T. Influence of cytochrome P-450 CYP2C9 polymorphisms on warfarin sensitivity and risk of over-anticoagulation in patients on long-term treatment. Blood 2000; 96: 1816–9

    PubMed  CAS  Google Scholar 

  13. Aithal GP, Day CP, Kesteven PJ, et al. Association of polymorphisms in the cytochrome P450 CYP2C9 with warfarin dose requirement and risk of bleeding complications. Lancet 1999; 353: 717–9

    Article  PubMed  CAS  Google Scholar 

  14. Higashi MK, Veenstra DL, Kondo LM, et al. Association between CYP2C9 genetic variants and anticoagulation-related outcomes during warfarin therapy. JAMA 2002; 287: 1690–8

    Article  PubMed  CAS  Google Scholar 

  15. Kirchheiner J, Brosen K, Dahl ML, et al. CYP2D6 and CYP2C19 genotype-based dose recommendations for antidepressants: a first step towards subpopulation-specific dosages. Acta Psychiatr Scand 2001; 104: 173–92

    Article  PubMed  CAS  Google Scholar 

  16. Dean FB, Hosono S, Fang L, et al. Comprehensive human genome amplification using multiple displacement amplification. Proc Natl Acad Sci U S A 2002; 99: 5261–6

    Article  PubMed  CAS  Google Scholar 

  17. Radi D, Esmaili L, Lally B, et al. Electrochemical detection of CYP2D6, CYP2C9 and CYP2C19 polymorphisms using eSensor™ DNA microarrays [abstract]. J Mol Diagn 2002; 4: 236

    Google Scholar 

  18. Romkes M, Faletto MB, Blaisdell JA, et al. Cloning and expression of complementary DNAs for multiple members of the human cytochrome P450IIC subfamily. Biochemistry 1991; 30: 3247–55

    Article  PubMed  CAS  Google Scholar 

  19. Xie H-G, Kim RB, Wood AJJ, et al. Molecular basis for ethnic differences in drug disposition and response. Ann Rev Pharmacol Toxicol 2001; 41: 815–50

    Article  CAS  Google Scholar 

  20. Shi MM. Technologies for individual genotyping: detection of genetic polymorphisms in drug targets and disease genes. Am J Pharmacogenomics 2002; 2: 197–205

    Article  PubMed  CAS  Google Scholar 

  21. Chou WH, Yan FX, Robbins-Weilert DK, et al. Comparison of two CYP2D6 genotyping methods and assessment of genotype-phenotype relationships. Clin Chem 2003; 49: 542–51

    Article  PubMed  CAS  Google Scholar 

  22. Borlak J, Thum T. Identification of major CYP2C9 and CYP2C19 polymorphisms by fluorescence resonance energy transfer analysis. Clin Chem 2002; 48: 1592–4

    PubMed  CAS  Google Scholar 

  23. Lyon E. Mutation detection using fluorescent hybridization probes and melting curve analysis. Expert Rev Mol Diagn 2001; 1: 92–101

    Article  PubMed  CAS  Google Scholar 

  24. Umek RM, Lin SW, Vielmetter J, et al. Electronic detection of nucleic acids: a versatile platform for molecular diagnostics. J Mol Diagn 2001; 3: 74–84

    Article  PubMed  CAS  Google Scholar 

  25. Taylor JD, Briley D, Nguyen Q, et al. Flow cytometric platform for high-throughput single nucleotide polymorphism analysis. Biotechniques 2001; 30: 661–6

    PubMed  CAS  Google Scholar 

  26. Iannone MA, Li MS, Taylor JD, et al. A microsphere-based assay for multiplexed single nucleotide polymorphism analysis using single base chain extension. Genome Res 2000; 10: 549–57

    Article  PubMed  Google Scholar 

  27. Ye F, Li MS, Taylor JD, et al. Fluorescent microsphere-based readout technology for multiplexed human single nucleotide polymorphism analysis and bacterial identification. Hum Mutat 2001; 17: 305–16

    Article  PubMed  CAS  Google Scholar 

Download references

Acknowledgments

We would like to acknowledge Motorola Life Sciences for providing the instrumentation and reagents to evaluate and support testing with the eSensor™ DNA detection system. We also thank Luminex Corporation for providing reagents for evaluation. ## The authors have no conflicts of interest that are directly relevant to the content of this study.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jerry W. Pickering.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Pickering, J.W., McMillin, G.A., Gedge, F. et al. Flow Cytometric Assay for Genotyping Cytochrome P450 2C9 and 2C19. Am J Pharmacogenomics 4, 199–207 (2004). https://doi.org/10.2165/00129785-200404030-00007

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.2165/00129785-200404030-00007

Keywords

Navigation