Arsenic, GSTO2 Asp142 polymorphism, health and treatment

Arsenic is a natural metallic element found in low concentrations in virtually every part of the environment, including waters and foods. The ingestion of arsenic by humans can cause a variety of disorders. Glutathione S-transferase omega (GSTO) is a member of phase II xenobiotic metabolizing enzymes. GSTO2 (a member of GST omega) participates in detoxification of inorganic arsenic. In human, the A>G transition at nucleotide position 424 of GSTO2 was reported. This variation causes an Asn142Asp substitution. The Asp142 allozyme was expressed at approximately 80 % of the level of Asn142 allozyme. It is hypothesized that the GSTO2 polymorphism may alter the risk of several diseases which are related to chronic arsenic poisoning. On the other hand, because arsenic trioxide is used for treatment of acute promyelocytic leukemia; it is possible that Asn142 allozyme may decrease the therapeutic effect(s) of the drug