Distribution of drug-metabolizing enzymes coding genes CYP2D6, CYP3A4, CYP3A5 alleles in a group of healthy Turkish population

Abstract

Abstract Objective: Variant alleles in specific ethnic groups are important for personalized drug therapy regimens and adverse drug reactions. Therefore, the aim of this study was to investigate allelic frequencies of the CYP2D6*1, CYP3A4*5, CYP3A4*18, CYP3A5*2 and CYP3A5*4 in a group of Turkish population. Materials and methods: Three hundred and six unrelated healthy subjects who were accepted as blood donors to the Mersin University Blood Bank were included in the study after informed consent. Allelic frequencies of the CYP2D6*1 (rs3892097), CYP3A4*5 (rs55901263), CYP3A4*18 (rs28371759), CYP3A5*2 (rs28365083) and CYP3A5*4 (rs56411402) were determined by using polymerase chain reaction-restriction fragment length polymorphism assays. Results: CYP2D6 allele frequencies in detected group was 100% for CYP2D6*1 (WT/WT). CYP3A4 allele frequencies of subjects were 100% for CYP3A4*5 (C/C) and CYP3A4*18 (T/T). CYP3A5 allele were in Hardy-Weinberg equilibrium for CYP3A5*2 (p=0.142) and frequencies for C and A allele were 91% and 9% respectively. CYP3A5 allele frequencies of subjects was 100% for CYP3A5*4 (WT/WT). Conclusion: Screening of low frequency alleles by pharmacogenetic testing must not be omitted to optimize pharmacotherapy and avoid severe drug toxicities. Frequency distributions of the identified polymorphisms in the present study may contribute to the personalized drug therapy regimens and prediction of possible adverse drug reactions in the Turkish population.