genotype and allele frequency of cyp2c19*17 in a healthy iranian population

background: cytochrome p450 2c19 (cyp2c19) is important in metabolism of wide range of drugs. cyp2c19*17 is a novel variant allele which increases gene transcription and therefore results in ultra-rapid metabolizer phenotype (urm). distribution of this variant allele has not been well studied worldwide. the aim of present study was to investigate allele and genotype frequencies of cyp2c19*17 in a healthy iranian population and compare them with other ethnic groups.   methods : one hundred eighty healthy unrelated iranian volunteer took part in this study and were genotyped for cyp2c19 *2, *3, *17 (-3402) by using polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) and cyp2c19*17 (-806) by a nested-pcr assays. the distribution of cyp2c19*17 polymorphism in iranian population was then compared with other ethnic groups.   results : the cyp2c19*17 allele frequency was 21.6% in iranian population. among studied subjects 5.5% were homozygous for cyp2c19*17 and phenotyped as ultra-rapid metabolizers 28.8% were genotyped as cyp2c19*1*17 (extensive metabolizers) and 3.3% as cyp2c19*2*17 (intermediate metabolizers).   conclusion : the cyp2c19*17 genetic distribution in iranian population is similar to middle east or european countries. the high frequency of cyp2c19*17 in iranian population highlights the importance of this new variant allele in metabolism of cyp2c19 substrates. thus, future association studies are required to reveal clinical consequence of this genetic polymorphism in carrier individuals.