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CYP2C9 and VKORC1 genetic polymorphism analysis might be necessary in patients with Factor V Leiden and prothrombin

Allen Leung1, Chih-Kang Huang, Riho Muto

  • 1Molecular Pathology Laboratory, Department of Pathology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10467, USA.

Diagnostic Molecular Pathology : the American Journal of Surgical Pathology, Part B
|August 28, 2007
PubMed

Insights

Genetic testing for CYP2C9 and VKORC1 variants is recommended for patients with Factor V Leiden or prothrombin gene mutations. This helps personalize warfarin dosing and reduce bleeding risks in hypercoagulable individuals.

Area of Science:

  • Pharmacogenomics
  • Thrombophilia

Background:

  • Venous thromboembolism (VTE) affects approximately 1 in 1000 person-years, primarily in older adults.
  • Factor V Leiden and prothrombin G20210A mutations are common inherited risk factors for hypercoagulability.
  • Warfarin anticoagulant therapy necessitates regular monitoring via the international normalization ratio (INR).

Purpose of the Study:

  • To investigate the necessity of CYP2C9 and VKORC1 genotyping in patients with inherited thrombophilia.
  • To assess the prevalence of specific CYP2C9 and VKORC1 genotypes in individuals with Factor V Leiden and/or prothrombin G20210A mutations.
  • To determine if genetic screening is warranted prior to warfarin initiation in this patient cohort.

Main Methods:

  • Analysis of 35 patient samples for Factor V Leiden and prothrombin G20210A mutations.
  • Genotyping for CYP2C9*2, CYP2C9*3, and VKORC1 (-1639 G>A) polymorphisms using the Invader assay.
  • Correlation of genetic variants with potential warfarin dose adjustments and bleeding risks.

Main Results:

  • 83% (29/35) of analyzed samples exhibited at least one of the target CYP2C9 or VKORC1 genotypes (CYP2C9*2 C/T, CYP2C9*3 A/C, VKORC1 (-1639) G/A, or VKORC1 (-1639) A/A).
  • Specific genotypes (CYP2C9*2, CYP2C9*3, VKORC1*2) are associated with significantly reduced warfarin doses and increased bleeding risk.
  • A high prevalence of relevant pharmacogenetic variants was observed in patients with inherited thrombophilia.

Conclusions:

  • CYP2C9 and VKORC1 genotyping may be essential for patients with Factor V Leiden and/or prothrombin G20210A mutations.
  • Personalized warfarin therapy based on pharmacogenetic profiles can mitigate risks associated with these mutations.
  • Pre-treatment genetic screening can optimize warfarin management and improve patient safety.

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