title: Allele and genotype frequencies of CYP2B6 and CYP2C19 polymorphisms in Egyptian agricultural workers.
abstract: Genetic variability in cytochrome P-450 (CYP) has the potential to modify pharmacological and toxicological responses to many chemicals. Both CYP2B6 and CYP2C19 are pharmacologically and toxicologically relevant due to their ability to metabolize multiple drugs and environmental contaminants, including the organophosphorus (OP) pesticide chlorpyrifos. The aim of this study was to determine the prevalence of CYP2B6 and CYP2C19 variants in an indigenous Egyptian population (n = 120) that was shown to be occupationally exposed to chlorpyrifos. Further, the genotyping data was compared for Egyptians with previously studied populations to determine between population differences. Allelic frequencies were CYP2B6 1459C > T (3.8%), CYP2B6 785A > G (30.4%), CYP2B6 516G > T (28.8%), CYP2C19 681G > A (3.8%), and CYP2C19 431G > A (0%). The most prevalent CYP2B6 genotype combinations were CYP2B6 *1/*1 (44%), *1/*6 (38%), *6/*6 (8%), and *1/*5 (6%). The frequency of the CYP2C19 genotype combinations were CYP2C19 *1/*1 (93%), *1/*2 (6%), and *2/*2 (1%). The frequency of the CYP2B6 516G > T and CYP2B6 785A > G polymorphisms in this Egyptian cohort is similar to that found North American and European populations but significantly different from that reported for West African populations, while that of CYP2B6 1459C > T is similar to that found in Africans and African Americans. The observed frequency of CYP2C19 681G > A in Egyptians is similar to that of African pygmies but significantly different from other world populations, while CYP2C19 431 G > A was significantly different from that of African pygmies but similar to other world populations.
authors.affiliation: Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214, USA. cellison@buffalo.edu
authors.forename: Corie A
authors.initials: CA
authors.lastname: Ellison
authors.forename: Soheir S
authors.initials: SS
authors.lastname: Abou El-Ella
authors.forename: Maha
authors.initials: M
authors.lastname: Tawfik
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Lein
authors.forename: James R
authors.initials: JR
authors.lastname: Olson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000383:Agriculture; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D004390:Chlorpyrifos; D015331:Cohort Studies; D065702:Cytochrome P-450 CYP2B6; D065731:Cytochrome P-450 CYP2C19; D004534:Egypt; D005787:Gene Frequency; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D007306:Insecticides; D008297:Male; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D016273:Occupational Exposure; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012463:Saliva / Q000737:chemistry; D055815:Young Adult
chemical_list: D005819:Genetic Markers; D007306:Insecticides; D001189:Aryl Hydrocarbon Hydroxylases; C585599:CYP2B6 protein, human; C045793:CYP2C19 protein, human; D065702:Cytochrome P-450 CYP2B6; D065731:Cytochrome P-450 CYP2C19; D010089:Oxidoreductases, N-Demethylating; D004390:Chlorpyrifos