Polymorphisms in the gene Arsenic 3 Metiltransferase (As3MT) associated to arsenic metabolism in the population of the Yaqui Valley, Sonora, Mexico

Abstract

Chronic arsenic exposure increases risk for the development of diabetes, vascular disease, and cancers of the skin, lung, kidney and bladder (Bredfeldt et al., 2004). The goal of this study was to evaluate the genetic association between the concentrations of inorganic arsenic metabolites in urine [(arsenite (AsIII), arsenate (AsV), metilarsinic acid (MMAV) and dimetilarsinic acid (DMAV)] and the gene As3MT which is involved in the metabolism of arsenic in residents adults chronically exposed to low arsenic concentrations in the drinking water from the Yaqui valley in Sonora, Mexico. The period of study was August, 2005 - August, 2007. Two communities from the Yaqui valley were selected; an urban community with arsenic concentrations in their well water of 48.4 ppb, and the other with 3.4 ppb. 151 study subjects were included and urine samples were taken for arsenic analysis and its metabolites according to the procedure 3015 of the US-EPA and determined by HPLC/ICP-MS; also were sampled blood and buccal cells for DNA isolation and analysis of polymorphisms in the gene As3MT according to the technique described by Meza and collaborators (2005). STATA 9.0 software was used in order to realize the correlations of the urinary arsenic species with the polymorphisms detected. The results showed that the proportions of urinary arsenic metabolites were: 45.0% of inorganic arsenic, 8.0% of MMAV and 46.2% of DMAV. Inorganic arsenic had the highest proportion in urine compared to other reports. The frequency of the genotypes in As3MT in the study population was 2.8% CC, 21.1% CT and 76.0% TT. Was not found genetic association between the genotypes of the gene As3MT and the arsenic levels in urine of the population for both communities. However the variable sex showed a strong statistical association with the dependent variables studied.