title: Genetic variability of CYP2C19 in a Mexican population: contribution to the knowledge of the inheritance pattern of CYP2C19*17 to develop the ultrarapid metabolizer phenotype.
abstract: CYP2C19 is a polymorphic enzyme that metabolizes a wide variety of therapeutic drugs that has been associated with altered enzymatic activity and adverse drug reactions. Differences in allele frequencies of the CYP2C19 gene have been detected in populations worldwide. Thus, we analysed the alleles CYP2C19*2, CYP2C19*3, CYP2C19*4 and CYP2C19*5 related to the poor metabolizer (PM) phenotype in a Mexican population sample (n = 238), as well as CYP2C19*17, unique allele related to ultrarapid metabolizer phenotype (UMs). Genotypes were determined using SNaPshot and TaqManqPCR assays. In addition to the wild-type CYP2C19*1 allele (77.1%), we only found CYP2C19*17 (14.3%) and CYP2C19*2 (8.6%). Comparison with previous population reports demonstrated that these two SNPs are homogeneously distributed in Latin America (P > 0.05). Based on comparison with a previous pharmacokinetic study that determined the frequency of CYP2C19 phenotypes in the same population (western Mexican), we obtained the following findings: (i) based on the difference between the frequency of genotypes CYP2C19*2/*2 (presumably PM) versus the observed prevalence of PM phenotypes (0.4 versus 6.3%; Χ(2) = 9.58, P = 0.00196), we inferred the plausible presence of novel CYP2C19 alleles related to the PM phenotype; (ii) the prevalence of UMs was in disagreement with the dominant inheritance pattern suggested for CYP2C19*17 (23.1 versus 4%; P < 0.00001); (iii) the apparent recessive inheritance pattern of CYP2C19*17, based on the agreement between homozygous CYP2C19*17/*17 (presumably UMs) and the observed prevalence of UMs (2.1 versus 4%; (Χ(2) = 1.048; P = 0.306).
authors.affiliation: Instituto de Investigacion en Genetica Molecular, Centro Universitario de la Cienega, Universidad de Guadalajara (CUCienega-UdeG), Av. Universidad #1115, Col. Lindavista, Ocotlan, Jalisco CP 47810, Mexico. hrangel13@hotmail.com.
authors.forename: Alma Faviola
authors.initials: AF
authors.lastname: Favela-Mendoza
authors.forename: Gabriela
authors.initials: G
authors.lastname: Martinez-Cortes
authors.forename: Marcelo
authors.initials: M
authors.lastname: Hernandez-Zaragoza
authors.forename: Joel
authors.initials: J
authors.lastname: Salazar-Flores
authors.forename: Jose Francisco
authors.initials: JF
authors.lastname: Muñoz-Valle
authors.forename: Victor Manuel
authors.initials: VM
authors.lastname: Martinez-Sevilla
authors.forename: Noemi Yolanda
authors.initials: NY
authors.lastname: Velazquez-Suarez
authors.forename: Hector
authors.initials: H
authors.lastname: Rangel-Villalobos
mesh_terms: D065731:Cytochrome P-450 CYP2C19 / Q000235:genetics*; D005787:Gene Frequency; D006801:Humans; D008658:Inactivation, Metabolic; D008800:Mexico; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide
chemical_list: C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19
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