Diversity of glutathione s-transferase omega 1 (a140d) and 2 (n142d) gene polymorphisms in worldwide populations.

1. Glutathione S-transferase class omega (GSTO) 1 and 2 are members of the glutathione-S-transferase family, which uses glutathione in the process of the biotransformation of drugs, xenobiotics and oxidative stress. Associations with the age-at-onset of Alzheimer's and Parkinson's diseases have been shown in the genetic polymorphism of GSTO1 and GSTO2. 2. In the present study, the frequencies of GSTO1A140D and GSTO2N142D in Ovambos (n = 163), Turks (n = 194), Mongolians (n = 243) and Japanese (n = 102) were investigated and compared with findings from other studies. Detection of these single nucleotide polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. 3. The allele frequencies of these polymorphisms in Ovambos, Turks, Mongolians and Japanese were 0.040, 0.085, 0.128 and 0.108, respectively, for GSTO1A140D and 0.583, 0.219, 0.173 and 0.216, respectively, for GSTO2N142D. Ovambos showed the lowest allele frequency of GSTO1A140D. Conversely, Africans, including Ovambos, showed higher allele frequencies of GSTO2N142D than Caucasians and Asians. 4. The existence of a certain genetic heterogeneity in the worldwide distribution of these two polymorphisms is revealed in the present study.