Tabriz University of Medical Sciences Journal of Research in Clinical Medicine 2717-0616 4 2 2016 05 31 Cytochrome P4502C19*3 allelic variant frequency in Iranian healthy Azeri Turkish population 110 114 10.15171/jarcm.2016.018 EN Nasim Alsadat Didevar Gholamreza Niaei Majid Farshdousti Hagh Bita Amir Taghavi Journal Article 10.15171/jarcm.2016.018 2016 01 05 2016 02 14 Introduction: Cytochrome P4502C19 (CYP2C19) is well-known to be one of the determinants responsible for the pronounced interethnic and individual differences in response and character of clinically important drugs. CYP2C19*3 arises from a G to A transition at position 636 in exon 4 of CYP2C19. These individuals be situated poor metabolizers (PMs) of a wide range of medications including omeprazole (OMP). In this study, we determined genotypes of CYP2C19*3 in Iranian Azeri Turkish population to compare allele frequencies with previous findings in other ethnic groups. Methods: CYP2C19*3 allelic variant was determined in 200 unrelated healthy Iranian volunteers by polymerase chain reaction-restriction fragment length polymorphism assays (PCR-RFLP). Results: The frequencies of CYP2C19*3 in healthy volunteers reported in this study (P = 0.569, χ2 = 2.35). This is not higher than that would be predicted from the genotypic status of these cases in CYP2C19*3 allelic variants. Our results revealed that 95.46% had wild type allele, they did not carry any of the tested mutations and 9 (4.54%) had mutant alleles. Conclusion: Our data recommend that genotyping for CYP2C19*3 is interest in using pharmacokinetics to individualize medicine, but results of this study demonstrated that CYP2C19*3 genetic polymorphism is not important determinant of the efficacy of PM of drugs, such as OMP, which may be metabolized by this enzyme.