Thiopurine S-methyltransferase in Han Chinese and Yao Chinese Children in Guangdong Liannan District

OBJECTIVE: This study was to investigate the activity distribution of thiopurine S-methyltransf erase (TPMP), and allelic frequency of four common TPMT mutant alleles in Han Chinese children (n=87) and Yao Chinese children (n=126) in Guangdong Liannan district. METHODS: A HPLC assay was used to measure Erythrocyte TPMT activity. Allele-specific PCR (ASPCR) and PCR-restriction fragment length polymorphism (RFLP) were used for analysis of TPMT2 (G238C), TPMT3A (G460A/A719G), TPMT3B (G460A) and TPMT3C (A719G). RESULTS: Unimodal distribution of TPMT activity was found in both Han Chinese children and Yao Chinese children. There was no significant difference in mean TPMT activity between Han Chinese and Yao Chinese children (13.01±2.80 versus 13.54 ± 3.89 U·ml-1 pRBC respectively). Only TPMT3C heterozygote was found in one Han Chinese child whose TPMT activity was 12.36 U·ml-1 pRBC, and the total frequency of mutant TPMT alleles in Han Chinese children was 0.6% (1/174). No mutant allele was found in Yao Chinese children. CONCLUSION: There were no statistically significant differences in both TPMT activity distribution and total frequency of mutant TPMT alleles between Han Chinese and Yao Chinese children in Guangdong Liannan district.