Abstract: Objective To conduct molecular epidemiological investigations on Han and Buyi women at Libo county of Guizhou province aiming for the identification of genetic polymorphisms coding the key enzymes for folate metabolism MTHFR and MTRR. Methods A total of 1 342 healthy women who received perinatal health care at the People's Hospital of Libo county were recruited, including 236 Han people and 1 106 Buyi people. Oral mucosal epithelial exfoliated cells were collected for genomic DNA extraction, MTHFR C677T, A1298C, and MTRR A66G gene polymorphisms were examined with quantitative PCR for statistical analysis. Results 1)The genetic polymorphism distribution of the subjects was in line with genetic balance. 2)The genotype frequency of MTHFR 677CC, CT, and TT of Han women was 49.6%, 39.8%, and 10.6% respectively,and that of Buyi women were 61.8%,33.7% and 4.4%. The frequencies were 62.3%, 33.1%, 4.7%, and Buyi females were 47.4%, 42.9%, and 9.7%, both points are significantly different(P＜0.05). The genotype frequencies of MTRR 66AA, AG, and GG of Han women were 56.4%, 37.4%, and 5.9%, respectively, and that of Buyi women were 57.0%, 36.0%, and 7.1%, with no difference. 3)Han and Buyi women MTHFR C677T and A1 298C had 6 combinations of two-point linkage without CT/CC, TT/AC and TT/CC. The highest frequency of Han women was CT/AA, and the highest frequency of Buyi women was CC/AC. The haplotype constructed by the two loci had three combinations of CA, TA, and CC, and there was a complete linkage disequilibrium between the two loci. Conclusions The genetic characterization of MTHFR and MTRR polymorphisms in Han and Buyi women at Libo county provides a basis for guiding folic acid supplementation and implementation of personalized pregnancy health care.

Key words: gene polymorphism, methylenetetrahydrofolate reductase(MTHFR), methionine synthase reductase(MTRR)