en داروسازی Pharmacology پژوهشي Research <p><b>Background:</b> Cytochrome P450 2C19 (CYP2C19) is a polymorphically expressed enzyme that shows marked interindividual and interethnic variation. CYP2C19*2 and CYP2C19*3 are the most frequently identified defective alleles in Orientals and Caucasian poor metabolizers (PM). The aim of this study was to investigate the frequencies of CYP2C19*1, CYP2C19*2 and CYP2C19*3 alleles and CYP2C19 genotypes in the Mazandarani ethnic group among Iranian Population.&nbsp;<br> <b>Materials and Methods:</b> The study was conducted in 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..<br> <b>Results:</b> Of the alleles tested, CYP2C19*1, and CYP2C19*2, but not CYP2C19*3, were detected. The frequencies for CYP2C19 alleles *1, *2, and *3 were 91%, 9.0%, and 0.0%, respectively. The frequencies of CYP2C19 genotypes *1/*1, *1/*2, *1/*3, *2/*2, *2/*3 and *3/*3 were 84%, 14%, 0.0%, 2.0%, and 0.0%, respectively.<br> <b>Conclusion:</b> The result of the present study showed 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 frequencies of the studied alleles resulted significant differences between our sample and African and Eastern Asian populations.</p> CYP2C19, genotype, alleles, Mazandaran, Iranian 16 20 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-326-1&slc_lang=en&sid=1 Naghi Shahabi-Majd shahabimajd@yahoo.com 10031947532846005793 10031947532846005793 No Molecular and Cell Biology Research Centre Mohammad bagher Hashemi-Sotehoh hashemisoteh@gmail.com 10031947532846005794 10031947532846005794 No Molecular and Cell Biology Research Centre Baharak Habashi dr.habashi1390@yahoo.com 10031947532846005795 10031947532846005795 No Psychiatry and Behavioral Sciences Research Centre Mohammad reza Shiran mr.shiran@gmail.com 10031947532846005796 10031947532846005796 Yes Psychiatry and Behavioral Sciences Research Centre