Genotype and allele frequencies of polymorphic CYP2E1 in the Turkish population

Abstract

Cytochrome P4502E1 (CYP2E1) gene shows genetic polymorphisms that vary markedly in frequency among different ethnic and racial groups. We studied the genotype distributions and allele frequencies of three CYP2E1 polymorphisms: CYP2E1*5B (RsaI/PstI RFLP, C-1053T/G-1293C SNP, rs2031920 /rs3813867), CYP2E1*6 (DraI RFLP, T7632A SNP, rs6413432), and CYP2E1*7B (DdeI RFLP, G-71T SNP, rs6413420) by PCR/RFLP technique in a sample of 206 healthy subjects representing Turkish population. CYP2E1*5B polymorphism analysis yielded the genotype distribution as 96.12% for *1A/*1A (c1/c1), and 3.88% for *1A/*5B (c1/c2). The genotype frequencies for CYP2E1*6 polymorphism were found as 83.98% for *1A/*1A (T/T), 15.53% for *1A/*6 (T/A) and 0.49% for *6/*6 (A/A). For CYP2E1*7B (G-71T) polymorphism, the genotype frequencies were determined to be 86.89% for *1A/*1A (G/G), 12.62% for *1A/*7B (G/T) and 0.49% for *7B/*7B (T/T). Accordingly, the allele frequencies for *5B, *6 and *7B were 1.94, 8.25, and 6.80%, respectively. The genotype distributions of CYP2E1*5B and *6 in Turkish population were similar to those in other Caucasian populations, while differed significantly from East Asian populations. Recently, a novel and functionally important CYP2E1*7B polymorphism was identified in the promoter region. There have been few studies and limited data on CYP2E1*7B polymorphism frequency in the world and, so far, no information has been available for Turkish population. The genotype frequencies of CYP2E1*7B in Turkish population were found to be similar to those of other Caucasian populations. Population studies like this could be useful in assessing the susceptibility of different populations to chemical-induced diseases, including several types of cancer.

Association Between Glutathione S-Transferase Omega 1 A140D Polymorphism in the Turkish Population and Susceptibility to Non-Small Cell Lung Cancer

“…In addition, our results are in contrast with the fi ndings for the Turkish population reported by Takeshita et al (17), whose genotype distribution and allele frequencies are similar to those of African, Brazilian, and Eastern Asian populations. This is rather unexpected because polymorphism frequencies of xenobiotic metabolising enzyme genes studied in the Turkish population so far, namely CYP, mEH, and GST, are generally similar to other Caucasian populations (20)(21)(22)35). At this stage, we can only speculate about the reasons why our fi ndings differ, as both studies used the same methods, and sample sizes were similar.…”

Cytochrome P450 2E1 RsaI/PstI and DraI polymorphisms are risk factors for lung cancer in Mongolian and Han population in inner Mongolia

“…Distribution of CYP2E1 RasI/PstI alleles (c1, c2) and DraI alleles (D, C) varies much in different races [3,13] . Frequencies of allele c2 and C are 4% and 11% in European-Americans, 1% and 8% in African-Americans, 28% and 24% in Taiwanese [13] , 1.94% and 8.25% in Turkish population, respectively [3] .…”

“…Cytochrome P450 2E1 (CYP2E1) is a main 1111111  member of CYP450 family. CYP2E1 RsaI/PstI (c2) polymorphism has G→C substitution at 1293bp in 5'-untranslated region of CYP2E1 gene and introduces PstI restriction enzyme site, CTGCAǁG [3] which causes a decrease in enzymatic activity. CYP2E1 DraI (C) polymorphism has a T→A substitution at 7632bp in sixth intron and destroys the DraI restriction enzyme site [3] .…”

“…CYP2E1 RsaI/PstI (c2) polymorphism has G→C substitution at 1293bp in 5'-untranslated region of CYP2E1 gene and introduces PstI restriction enzyme site, CTGCAǁG [3] which causes a decrease in enzymatic activity. CYP2E1 DraI (C) polymorphism has a T→A substitution at 7632bp in sixth intron and destroys the DraI restriction enzyme site [3] . The RsaI/PstI and DraI mutations of CYP2E1 can reduce effects on the metabolism of precarcinogens in tobacco, showing a protective effect on the body.…”

Updated Meta-analysis of the Association Between CYP2E1 RsaI/PstI Polymorphisms and Lung Cancer Risk in Chinese Population

“…Two meta-analyses have reported that the CYP2E1 RsaI/ PstI c2 allele is a protective factor for developing lung cancer among Asians and all ethnic population (Wang et al, 2010b;Zhan et al, 2010). However, it is well established that the frequencies of CYP2E1 RsaI/PstI polymorphisms differ markedly among different ethnic and racial groups (Soya et al, 2005;Ulusoy et al, 2007;Shahriary et al, 2012;Lakkakula et al, 2013). Therefore, it is necessary to address this issue in different ethnic groups.…”