Genotype-Phenotype Analysis of CYP2C19 in Healthy Saudi Individuals and its Potential Clinical Implication in Drug Therapy

UNLABELLED CYP2C19 is a cytochrome P450 enzyme, which is involved in the metabolism of some clinically important medications and is encoded by a highly polymorphic gene. There is no available data on the distribution of the CYP2C19 *4 and *17 mutant alleles in the Saudi Arabian population. The aim of the study was to determine different CYP2C19 mutant allele (*2, *4 and *17) frequencies in healthy Saudi subjects and to determine genotype frequencies for these mutations. The CYP2C19 genotypes were then classified into phenotypes. RESULT In 201 adults of Saudi ethnicity, the allele frequencies were CYP2C19*1 (62.9%), *17 (25.7%), *2 (11.2%) and *4 (0.2%). The most prevalent genotype combinations were CYP2C19 *1/*1 (40.3%) and *1/*17 (30.4%). The distribution of CYP2C19 phenotypes was divided into extensive metabolizers (EM) 77.6%, intermediate metabolizers (IM) 14.9%, ultra-rapid metabolizers (UM) 7% and poor metabolizers (PM) 0.4%. This finding has important clinical implications for the use of CYP2C19 metabolized medications in the Saudi population and further studies are needed.