Author(s): Aquilante CL, Lobmeyer MT, Langaee TY, Johnson JA
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Abstract STUDY OBJECTIVE: To compare the accuracy, speed, and cost of two methodologies used for genotyping known variants in the cytochrome P450 (CYP) 2C9 metabolizing enzyme gene. DESIGN: Comparative study. SETTING: University research center. SAMPLES: Fifteen-milliliter mouthwash samples collected from 253 subjects participating in a warfarin pharmacogenomic study. INTERVENTION: Genotyping for the isoleucine-to-leucine change at codon 359 (Ile359Leu [*3] polymorphism) was performed by using the Pyrosequencing and polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods in all 253 samples. Genotyping for the arginine-to-cysteine change at codon 144 (Arg144Cys [*2] polymorphism) was performed by using Pyrosequencing in all samples and by PCR-RFLP in a random subset of 136 samples. MEASUREMENTS AND MAIN RESULTS: Comparisons of genotyping success rates, time efficiency, and cost analyses were conducted for Pyrosequencing and PCR-RFLP at each variant site. Pyrosequencing and PCR-RFLP produced similar success rates on the first genotyping attempt for the Arg144Cys variant (93.3\% vs 90.4\%, respectively) and the Ile359Leu variant (83.8\% vs 79.1\%, respectively). With Pyrosequencing, genotyping 96 samples for either polymorphism could be performed in 1 hour. In contrast, genotyping 96 samples by RFLP took 10 hours for the Arg144Cys variant and 20 hours for the Ile359Leu variant. Total cost/sample for Arg144Cys genotyping was dollars 1.90 with PCR-Pyrosequencing and dollars 3.14 with PCR-RFLP. Total cost/sample for Ile359Leu genotyping was dollars 1.88 with PCR-Pyrosequencing and dollars 10.18 with PCR-RFLP CONCLUSION: Compared with RFLP, genotype determination by Pyrosequencing is a more time-efficient, cost-effective, and robust method for CYP2C9 genotyping. Because of its wide applicability and ease of use, Pyrosequencing is a promising technology for future pharmacogenomic investigations.
This article was published in Pharmacotherapy
and referenced in Journal of Pharmacogenomics & Pharmacoproteomics