Pharmacogenetic study of methylenetetrahydrofolate reductase and thymidylate synthase in Japanese and assessment of ethnic and gender differences.
OBJECTIVE
We investigated the four polymorphisms of the 5,10-methylenetetrahydrofolate reductase (MTHFR) and thymidylate synthase (TYMS) genes that are related to the pharmacologically active sites of methotrexate for the treatment of rheumatoid arthritis in 102 healthy Japanese adults and assessed the possibility of ethnic and gender differences.


METHODS
Polymorphisms of MTHFR C677T, A1298C, the two or three 28-bp tandem repeats in the TYMS 5'-untranslated regions (UTR), and the 6-bp deletion/insertion in the TYMS 3'-UTR were measured using polymerase chain reaction with restriction fragment length polymorphism method. Published data on allelic frequencies by ethnic group and gender were collected from Medline.


RESULTS
Allelic frequencies in healthy Japanese adults were: MTHFR 677T allele 41%, MTHFR 1298C allele 22%, TYMS 5'-UTR 3R allele 84%, and TYMS 3'-UTR-6-bp allele 59%. Significant differences were found in the distribution of MTHFR C677T between black and Japanese populations, of TYMS 5'-UTR alleles between Caucasian or black and Japanese populations, and of TYMS 3'-UTR alleles between Caucasian and Japanese populations (p < 0.001). Moreover, a gender difference was found in TYMS 3'-UTR allelic frequency in Japanese (p = 0.015).


CONCLUSIONS
Ethnic and gender variations in the distribution of these allelic frequencies may associate with the difference in the effects of methotrexate in rheumatoid arthritis patients.
Inoue
Sachie
S
Kitasato University, Division for Evaluation and Analysis of Drug Information, Center for Clinical Pharmacy and Clinical Sciences, School of Pharmacy, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
Hashiguchi
Masayuki
M
Chiyoda
Takeshi
T
Sunami
Yukiko
Y
Tanaka
Takanori
T
Mochizuki
Mayumi
M
D000328:Adult; D044466:Asian People / Q000235:genetics*; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D010597:Pharmacogenetics / Q000379:methods*; D012727:Sex Characteristics; D013940:Thymidylate Synthase / Q000235:genetics*
D042965:Methylenetetrahydrofolate Reductase (NADPH2); D013940:Thymidylate Synthase