Correlation Between MTHFR Gene Polymorphism And Folic Acid Levels In Early Pregnancy In Women With Different Exposure Doses Of Folic Acid

Objectives:To investigate the effect of different doses of folic acid on methylenetetrahydrofolate reductase(MTHFR)and methionine synthase reductase(MTRR)gene polymorphisms and folate levels in early pregnancy in women with different folic acid doses,so as to prepare for early pregnancy and pregnant women.Accurate supplementation of folic acid provides a basis.Methods:This study selected 300 pregnant women who attended a gynecology and obstetrics clinic of a top three hospital in Kunming from July 2018 toJuly2019.The pregnant women who met the inclusion criteria were selected by filling in a self-made questionnaire on folic acid intake of women of childbearing age.Serum folic acid,RBC folic acid and homocysteine levels were measured by chemiluminescent immunoassay.MTHFR C677T and MTRR A66G sites were determined by quantitative RT-PCR.SPSS 25.0 statistical software was used to analyze the correlation between MTHFR and MTRR gene polymorphism and folic acid concentration in vivo.Results:1.Among the 300 pregnant women in Yunnan province,the C allele of MTHFR gene C677T(rs1801133)and T allele accounted for 62%and 38%respectively in the non-folic acid group.The C allele and T allele of the MTHFR C677T locus accounted for 62%and 38%respectively in the 0.4mg/d group.The C allele and T allele of the MTHFR C677T genotype were 64%and 36%respectively in the group receiving 0.8mg/d.A66G(rs1801394)A allele and G allele accounted for 72%and 28%of MTRR gene in the non-folic acid group.The A allele and the G allele of MTRR A66G genotype were 67.5%and 32.5%respectively in the 0.4mg/d group.The A allele of MTRR A66G genotype accounted for 74.5%and the G allele for 25.5%in the group receiving 0.8mg/d.2.There was no correlation between different MTHFR C677T genotypes and serum folic acid level(P=0.234>0.05)and Hcy(P=0.317>0.05).There was correlation between different genotypes and folic acid level of RBC(P=0.001,P<0.05).There was no correlation between different MTRR A66G genotypes and serum folic acid,RBC folic acid and Hcy levels(P values were 0.179,0.398 and 0.310,P>0.05).3.The correlation between the MTHFR C677T genotype and serum folic acid and RBC folic acid levels in 300 pregnant women with different folic acid exposure doses was analyzed:The difference was obvious verified by statistical method in serum folic acid and RBC folic acid levels between the non-folic acid group and the 0.8mg/d group(P<0.05).The levels of folic acid in red blood cells of different genotypes of MTHFR C677T in the 0.4mg/d group were significantly different(P<0.05),while the levels of serum folic acid were not significantly different(P=0.183,P>0.05).The correlation between the MTRR A66G genotype and serum folic acid and RBC folic acid levels in pregnant women with different folic acid exposure doses was analyzed.The difference was little verified by statistical method in serum folic acid and RBC folic acid levels between the non-folic acid group and the 0.4mg/d group(P values greater than 0.05).There was no statistical significance in the red blood cell folic acid level(P=0.163,P>0.05)in the group receiving 0.8mg/d with different MTRR A66G genotypes,while the serum folic acid level(P=0.041,P<0.05)had a significant difference.4.The difference was obvious verified by statistical method between serum folic acid level and homocysteine level(r=-0.245,P=0.000).Serum folate level was positively correlated with RBC folate level(r=0.621,P=0.000).There was a positive correlation between folic acid dose and serum folic acid level(r=0.696,P=0.000)and red blood cell folic acid level(r=0.933,P=0.000),and a negative correlation between folic acid dose and Hcy level(r=-0.185,P=0.001).5.The median concentration of folic acid in RBCs of pregnant women who did not receive folic acid was 846nmol/L,and the median concentration of folic acid in RBCs of pregnant women who received 0.4mg/d was 1183nmol/L,and the median concentration of folic acid in RBCs of pregnant women who received 0.8mg/d was 1703nmol/L.6.Analysis of age and BMI with serum folic acid,RBC folic acid and Hcy levels showed that the difference was little verified by statistical method in serum folic acid,RBC folic acid and Hcy between pregnant women of different ages and different BMI(P>0.05).7.There was no statistically significant difference between gestational age and serum folate(P=0.077),and there was a statistically significant difference between gestational age and RBC folate level and Hcy level(P<0.05).Conclusions:1.As the dose of folic acid increases,so does the level of folic acid in the body.Patients with different MTHFR C677T genotypes were gradually reduced by genetic risk.2.In patients with supplementation of 0.4mg/d and 0.8mg/d folic acid,the concentration of red blood cell folic acid reached the level of NTDs(906nmol/L)by WHO.3.Different doses of folic acid can affect levels of folic acid and homocysteine in the body,meaning that an increase in folic acid dose can increase the levels of folic acid in the serum and red blood cells,while reducing the levels of homocysteine.4.Red blood cell folic acid level increased with the increase of serum folic acid level.Age,BMI and gestational age were independent of serum folic acid,red blood cell folic acid and homocysteine levels.