The Diversity of CYP2C19 Polymorphisms in the Thai Population: Implications for Precision Medicine

plays a major role in the metabolism of various drugs. The most common genetic variants were the and alleles ( and , non-functional variants). In previous studies, we found that genetic polymorphisms in variants influenced the active metabolites of clopidogrel and caused major adverse cardiovascular and cerebrovascular effects. However, the distribution of varies among ethnic groups and according to adverse drug reactions. This study aimed to investigate the frequency of genetic polymorphisms in the Thai population and analyze the differences in the frequency of genetic polymorphisms between Thai and other populations. This study enrolled 211 unrelated healthy Thai individuals in total. We performed a real-time polymerase chain reaction to genotype (681G > A) and (636G > A). In the Thai population, the allele was the most prevalent at 70.14%, while the and alleles were found at frequencies of 25.36% and 4.50%, respectively. Conversely, the allele was not detected in Caucasian, Hispanic, African, Italian, Macedonian, Tanzanian, or North Indian populations. The phenotypic profile of this gene revealed that the frequency of intermediate metabolizers (IMs) is nearly equal to that of extensive metabolizers (EMs), at 42.65% and 48.82% respectively, with genotypes (36.02%) and (6.63%). Likewise, poor metabolizers (PMs) with genotypes (6.16%), (2.37%), and (