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A recent genome-wide association study provides significant data to confirm patients with variations in three specific genes are more likely to have adverse reactions to the anticoagulant warfarin.
Researchers studied approximately 326,000 SNPs in 1,053 Swedish individuals to detect genetic variants influencing warfarin dose requirements. Along with polymorphisms in two known warfarin-related genes, VKORC1 and CYP2C9, a third variant was found in a gene called CYP4F2 that also contributes to pateint response to warfarin and dose variability.
In 2007, the US Food and Drug Administration (FDA) updated warfarin guidelines to encourage testing for polymorphisms in the genes CYP2C9 and VKORC1. The FDA noted that one-third of patients metabolize warfarin more slowly than others and therefore experience a higher risk of bleeding. The FDA also stated that warfarin can be a difficult drug to manage due to its narrow therapeutic index and wide patient variability.
To assist physicians with prescribing the correct initial warfarin dose, MPLN offers the Verigene® Warfarin Metabolism Nucleic Acid Test (Nanosphere, Inc. Northbrook, IL). This pharmacogenetic test detects variations in the two well-known genes, CYP2C9 and VKORC1, which cause approximately 40% of the variability in warfarin dose.
According to the recent study, the newly discovered gene, CYP4F2, contributes 1-2% of the variability associated with warfarin dose response, an association the research team validated in almost 600 other Swedish patients.
For more information about the warfarin test offered by MPLN, contact a client service specialist at 800-932-2943. To read more about the genome-wide association study, visit www.plosgenetics.org. |
