TYMS and DPYD polymorphisms in a Turkish population.

OBJECTIVE: The thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) enzymes affect the outcome of 5-fluorouracil (5-FU)-based chemotherapy. Genetic polymorphisms of the thymidylate synthase (TYMS) and dihydropyrimidine dehydrogenase (DPYD) genes that may affect chemotherapy are described. The aim of this study was to determine the frequencies of TYMS and DPYD polymorphisms in healthy Turkish individuals. METHODS: Genotyping analyses of the promoter enhancer region of TYMS (TSER) and the exon 14-skipping mutation of the DPYD (DPYD*2A) genes were conducted in 250 unrelated, healthy volunteers from the central region of Turkey using a PCR-based assay. RESULTS: The distribution of the TSER*2/*2, *2/*3 and *3/*3 genotypes were 17.6%, 48.8%, and 33.6%, respectively. The frequencies of the TSER*2 and *3 alleles in the Turkish population were 0.42 and 0.58, respectively. No individuals with the variant DPYD*2A allele were identified in the study group. CONCLUSION: The frequency of the TSER*3 allele among members of the Turkish population was similar to frequencies observed in other Caucasian populations but was lower than those found in Japanese and Chinese populations.