Influence of genetic polymorphism on heavy metal toxicity – A review

Inter individual differences amongst species are known to influence the metabolism and toxicity of drugs/chemicals. The individual susceptibility has been attributed to the polymorphism of detoxication enzymes. For example 7700 individual CYPs (Phase-I enzymes) are known till date. Five isoforms of glutathiones-transferases (Phase-II enzymes) have also been described. Around sixty mutates are known for cytosolic superoxide dismutase. Mammalian metallothioneins are also genetically polymorphic. Polymorphism of glutamyl-cysteine ligare (GCL) and glutathione-S-transferase (GST) genes can modify the adverse drug reactors caused by xenobiotics. In this review the inter specific role of these mutate genes has been discussed for a few environmentally significant metals/metalloids viz.: arsenic, cadmium, mercury, lead, chromium and copper. Information presented reviews gene-metal interactions that determine the individual susceptibility to toxic metals. Pharmacogenomic biomarkers of metal toxicity might be the final outcome of such studies.