Pharmacogenomic variant profiling in 14,490 Koreans using a population-specific genotyping array

Pharmacogenomics is an essential component of precision medicine; however, most existing knowledge has been derived from populations of European ancestry, limiting the understanding of pharmacogenomic diversity in East Asian populations. In this study, we applied genotype imputation to the Korea Biobank Array v2.0 using a reference panel of 8,062 Korean whole-genome sequencing (WGS) samples and analyzed pharmacogenomic variants and phenotypes in 14,490 Korean individuals. To assess the accuracy of imputation-based variant detection, we compared imputed genotypes with matched WGS data from 735 individuals and with genotypes obtained from the commercial PangenomiX Plus Array Kit for an additional 137 individuals, demonstrating high concordance. When extended to the full cohort, all individuals were found to carry at least one pharmacogenomic variant, with high frequencies observed in key pharmacogenes including CYP2C19, SLCO1B1, CYP3A5, and VKORC1. Phenotype distributions were broadly consistent with previous WGS-based studies in East Asians but showed notable differences compared with European populations. Overall, this population-specific, large-scale analysis provides a comprehensive pharmacogenomic landscape in Koreans and highlights the importance of ancestry-tailored data for equitable precision medicine.