Genetic Polymorphisms as Modifiers of Health Risks from Exposure to Toxic Elements: A Traditional Literature Review

A growing body of epidemiological and toxicological evidence indicates that exposure to toxic elements (TEs), including As, Cd, Cr(VI), Pb, and Hg, is associated with a wide range of adverse health outcomes, including cancer, neurological and cardiovascular diseases. Given their widespread presence and toxicity, understanding the factors underlying inter-individual differences in susceptibility is essential, as not all exposed individuals develop the same health effects. Genetic variability, particularly single-nucleotide polymorphisms (SNPs), is increasingly recognized as a key determinant of individual responses to TE exposure. Variants in genes involved in metal transport, detoxification, and DNA repair, including DMT1, GSTP1, MT2A, hOGG1, and XRCC1, may influence internal dose and biological effects and have been proposed as potential susceptibility markers. However, current evidence remains inconsistent due to small sample sizes, heterogeneous exposure assessments, and limited considerations of ethnic diversity and gene–environment interactions. Future research should prioritize large and well-characterized populations integrating detailed exposure and lifestyle data. This review focuses on genetic susceptibility and gene–environment interactions in TE exposure, with particular emphasis on SNPs as key modulators of individual risk. It summarizes major toxic metals, reviews epidemiological evidence of the associated health risks, and highlights the role of genetic background in modulating TE-induced toxicity.