Distribution of genetic variants of oxidative stress metabolism genes: Paraoxonase 1 (PON1) and Glutathione S-transferase (GSTM1/GSTT1) in a population from Southeastern Mexico

Abstract

Background: Paraoxonase 1 (PON1) and glutathione S-transferases (GSTs) are involved in the biotransformation of xenobiotics. Variation in the enzyme concentration and activity suggests individual differences for the degree of protection against oxidative stress.Aim: This study analysed the distribution of SNPs Q192R, L55M (PON1) and variants in GSTM1 and GSTT1 genes in a population from Southeastern Mexico.Subjects and methods: One hundred and fifty-one Mexican Mestizo healthy volunteers were included. PON1 polymorphisms were determined by Taqman allele discrimination real time-PCR, whereas GSTM1 and GSTT1 genes were determined with a multiplex PCR-based method.Results: All genotypes were in Hardy-Weinberg equilibrium, except for GSTM1. The genotypic distributions of Q192R and L55M were 22% QQ, 48% QR, 30% RR, 62% LL, 34% LM and 4% MM, respectively, whereas the allele frequencies were 0.46 (Q), 0.54 (R), 0.79 (L) and 0.21 (M). The most frequent haplotype was R/L (46.7%). It was found that 31% and 9% of the individuals had the GSTM1 and GSTT1 null genotype, respectively. The frequency of the combined null genotype GSTM1*0/GSTT1*0 was 4.64%.Conclusion: The results showed that the frequencies of polymorphisms of PON1, GSTM1 and GSTT1 in the Yucatán population differ to those observed in other ethnic groups and provide useful data for epidemiological studies.