Molecular analysis of thiopurine S-methyltransferase alleles in Taiwan aborigines and Taiwanese

Thiopurine S-methyltransferase (TPMT) is a cytosolic enzyme involved in the metabolism of these thiopurine drugs. Methylation of thiopurine drugs by TPMT competes with the formation of their active 6-thioguanine nucleotide metabolite, thereby potentially modulating the therapeutic and toxic effects of these drugs. To analyze the thiopurine S-methyltransferase allelic frequencies in Taiwan aborigines and Taiwanese. We used polymerase chain reaction-restriction fragment length polymorphism method to determine the allelic frequencies of TPMT variants (TPMT*1-TPMT*8) in 409 Taiwan aborigines and 117 Taiwanese. The results showed that the allelic frequencies of TPMT*1 were 99.88% and 98.72% for Taiwan aborigines and Taiwanese respectively. The allelic frequencies of TPMT*3C were 0.12% and 1.28% for Taiwan aborigines and Taiwanese respectively. No TPMT*2, 3A, 3B, 3D and 4-8 were found in these populations. Our results provide useful information for using thiopurine drugs in these populations.