4CPS-200 Differences in allelic frequencies of relevant pharmacogenetic polymorphisms may lead to local gene panel development

Background and importance Pharmacogenetics allows identification and prediction of different responses to drugs in patients. During the past few years, pharmacogenetic dosing guidelines have been developed and implemented in daily clinical practice around the world. Furthermore, different companies and institutions have developed gene panels, including clinically relevant genes, to make genetics useful in clinical practice. But not all single nucleotide polymorphisms (SNP) in these genes affecting drug responses are similarly relevant among populations if we look at their allelic frequencies, even in the same country. In the future, this may lead to the design of local gene panels for pharmacogenetic implementation in clinical practice, depending on the population. Aim and objectives The aim of this study was to find, among the SNPs studied by the pharmacogenetics unit of our hospital, those with different allelic frequencies compared with the Iberian Peninsula population. Material and methods The patients´ genotypes of all the SNPs studied by the pharmacogenetics unit were recorded since the first pharmacogenetic test in 2012.The SNPs were genotyped using predesigned TaqMan genotyping assays or KASP assay and analysed on a7900HT Fast Real Time PCR System (Applied Biosystems). Allelic frequencies of the studied SNPs were calculated and compared with those reported in the 1000 Genomes Project for the Iberian Peninsula population using the χ2 test or Fisher’s exact test. A p value Results Since the first pharmacogenetic test performed by our department, 7678 tests in 2287 patients, affecting 7 drugs, were performed. Altogether, 27 different SNPs were genotyped. From these, we found that three SNPs showed significant differences in their allelic frequencies compared with those reported by the 1000 Genomes Project for the Iberian Peninsula population. These were: ABCB1 C3435T (c3435T>C; rs1045642) that showed a minor allele frequency of 53.7% in the Iberian population and 54.8% in our population (p=0.011); CYP2D6 gene duplication (10% vs 2.6%; p=0.049); and CYP2D6*5 (gene deletion) (7% vs 0%; p=0.014) Conclusion and relevance There were differences in allelic frequencies between relevant pharmacogenetic polymorphisms comparing a subpopulation of the 1000 Genomes Project and one of its sub-subpopulations. References and/or acknowledgements No conflict of interest.