<a name="home"></a>CYP2A6 and CYP2E1 polymorphisms in a Brazilian population living in Rio de Janeiro

Abstract

Cytochrome P450 (CYP) is a superfamily of enzymes involved in the metabolism of endogenous compounds and xenobiotics. CYP2A6 catalyzes the oxidation of nicotine and the activation of carcinogens such as aflatoxin B1 and nitrosamines. CYP2E1 metabolizes ethanol and other low-molecular weight compounds and can also activate nitrosamines. The CYP2A6 and CYP2E1 genes are polymorphic, altering their catalytic activities and susceptibility to cancer and other diseases. A number of polymorphisms described are ethnic-dependent. In the present study, we determined the genotype and allele frequencies of the main CYP2A6 and CYP2E1 polymorphisms in a group of 289 volunteers recruited at the Central Laboratory of Hospital Universitário Pedro Ernesto. They had been residing in the city of Rio de Janeiro for at least 6 months and were divided into two groups according to skin color (white and non-white). The alleles were determined by allele specific PCR (CYP2A6 ) or by PCR-RFLP (CYP2E1). The frequencies of the CYP2A6*1B and CYP2A6*2 alleles were 0.29 and 0.02 for white individuals and 0.24 and 0.01 for non-white individuals, respectively. The CYP2A6*5 allele was not found in the population studied. Regarding the CYP2E1*5B allele, we found a frequency of 0.07 in white individuals, which was statistically different (P < 0.05) from that present in non-white individuals (0.03). CYP2E1*6 allele frequency was the same (0.08) in both groups. The frequencies of CYP2A6*1B, CYP2A6*2 and CYP2E1*6 alleles in Brazilians are similar to those found in Caucasians and African-Americans, but the frequency of the CYP2E1*5B allele is higher in Brazilians.

Frequencies of 23 Functionally Significant Variant Alleles Related with Metabolism of Antineoplastic Drugs in the Chilean Population: Comparison with Caucasian and Asian Populations

“…Some polymorphisms have been studied in other South American countries (Isaza et al, 2000; Gaspar et al, 2002; Fernández et al, 2004; Gattas et al, 2004; Vianna-Jorge et al, 2004; Almeida et al, 2005; Lizcano Fernández, 2005; Rossini et al, 2006; Schlawicke et al, 2007; Canalle et al, 2008; Rodríguez et al, 2008; Castaño-Molina et al, 2009; Dorado et al, 2011), but the comparison with Chilean Mestizo population is very difficult because of the divergent origin of these populations. Chilean population is different from other South American countries, from Brazilian people for example, which have African and Portuguese contribution with great pharmacogenomic diversity, or from Argentina and Uruguay populations, which are multiethnic countries, with Amerindian-European admixture, but mostly with Italians (Lizcano Fernández, 2005).…”

Genetic polymorphisms of drug‐metabolizing phase I enzymes CYP2E1, CYP2A6 and CYP3A5 in South Indian population

“…The CYP2A6*2 genotype and allele frequencies were found to be significantly lower in South Indians than in Caucasians, Finns and Spaniards [48,49]. There was no significant difference between South Indians, African American and Chinese.…”

Functional PstI/RsaI Polymorphisms in the CYP2E1 Gene among South Indian Populations

“…The c2 mutant allele frequency varies in the European populations ranges from 3.47% to 5.5% (Tang et al, 2010). Analysis of Brazilian populations revealed variations in the c2 mutant allele frequency between white and non-white individuals (Rossini et al, 2006). The c2 allele frequency is higher in Mexicans as compared with other Native American populations (Mendoza-Cantu et al, 2004).…”