ABSTRACT
Cytochrome P450 2C19 [CYP2C19] is a polymorphically expressed enzyme that shows marked interindividual and interethnic variation. CYP2C19[asterisk]2 and CYP2C19[asterisk]3 are the most frequent identified defective alleles in Orientals and Caucasian poor metabolizers [PM]. The aim of this study was to investigate the frequencies of CYP2C19[asterisk]1, CYP2C19[asterisk]2 and CYP2C19[asterisk]3 alleles and CYP2C19 genotypes among Mazandarani ethnic group among Iranian Population. The study was conducted on 103 unrelated healthy volunteers. DNA was extracted from leucocytes and analyzed by the PCR-RFLP protocol. The PCR product was digested with restriction enzymes [SmaI and BamH1] and then separated electrophoretically using polyacrylamide gel. Of the tested alleles, CYP2C19[asterisk]1, and CYP2C19[asterisk]2, but not CYP2C19[asterisk]3, were detected. The frequencies for CYP2C19 alleles [asterisk]1, [asterisk]2, and [asterisk]3 were 91%, 9.0%, and 0.0%, respectively. CYP2C19 genotypes [asterisk]1/[asterisk]1, [asterisk]1/[asterisk]2, [asterisk]1/[asterisk]3, [asterisk]2/[asterisk]2, [asterisk]2/[asterisk]3 and [asterisk]3/[asterisk]3 frequencies were 84%, 14%, 0.0%, 2.0%, and 0.0%, respectively. The result of the present study shows that the two inactive alleles of CYP2C19 accounted for 9.0% of CYP2C19 alleles in our sample versus 8.8 - 40.1% reported in other populations. The frequency of alleles was significant. Differences between our sample and African and Eastern Asian populations