Genetic Polymorphism Influencing Arsenic Metabolism in Human

Groundwater pollution by arsenic is a serious worldwide problem, especially in developing Asian and African countries. Large inter-individual variation in the arsenic metabolism has been reported. Human arsenic (+3 oxidation state) methyltransferase (AS3MT) is known to catalyze the methylation of arsenite. The M287T polymorphism in AS3MT is considered to be related to inter-individual variation in the arsenic metabolism. Several genetic polymorphisms within AS3MT genes in the Japanese, Koreans, Chinese, Mongolians, Uygurs, Tibetans, Vietnamese, Tamangs, Tamils, and Sinhalese in Asia and the Ovambos, Ghanaians, and Xhosas in Africa were investigated. Population differences were observed in the only M287T polymorphism in AS3MT. The Asian populations had 287T variant allele frequencies ranging from 0.000 to 0.041, relatively lower than those of the Africans and Caucasians. The other polymorphisms within AS3MT did not show such ethnic differences. Our findings indicate that the genetic susceptibility to arsenic toxicity in Asian populations is different from that in Africans and Caucasians.