Polymorphisms of the methylenetetrahydrofolate reductase gene (C677T and A1298C) in nulliparous women complicated with preeclampsia

MTHFR A1298C polymorphism: a predictor of reduced risk of preeclampsia in Punjab, Pakistan

OBJECTIVES

This study aimed to investigate the genetic association between MTHFR (A1298C) SNP and preeclampsia (PE) in Punjab, Pakistan.

METHODS

A sample of 80 pregnant women (40 healthy pregnant women and 40 with PE) was pooled for genotyping MTHFR A1298C polymorphism by using the tetra-primer amplification refractory mutation system (ARMS) PCR. The Genotypic and allelic assessments were performed using various statistical techniques.

RESULTS

The AC genotype and C allele of MTHFR A1298C were found to be associated with decreased risk of PE (odds ratio [OR]: 0.31, risk ratio [RR]: 0.58, p = 0.01), and (odds ratio [OR]: 0.49, risk ratio [RR]: 0.61, p = 0.04), respectively.

CONCLUSION

In conclusion, genetic polymorphism A1298C in MTHFR may pose a protective effect in the studied population.

Polymorphisms in gene MTHFR modify the association between gestational weight gain and adverse birth outcomes

Evidence suggests a potential relationship between gestational weight gain (GWG) and adverse birth outcomes. However, the role of maternal genetic polymorphisms remains unclear. This study was conducted to investigate whether the relationship of GWG with risk of adverse birth outcomes was modified by methylenetetrahydrofolate reductase (MTHFR) polymorphisms. A total of 2,967 Chinese pregnant women were included and divided into insufficient, sufficient, and excessive groups based on the Institute of Medicine (IOM) criteria. Polymorphisms of C677T and A1298C in gene MTHFR were genotyped. Multivariable logistic regression models were introduced after controlling major confounders. Excessive GWG was found to increase the odds ratio (OR) for macrosomia [OR = 3.47, 95% confidence interval (CI): 1.86–6.48] and large-for-gestational age (LGA, OR = 3.25, 95% CI: 2.23–4.74), and decreased the OR for small-for-gestational age (SGA, OR = 0.60, 95% CI: 0.45–0.79). Pregnant women with insufficient GWG had a higher frequency of SGA (OR = 1.68, 95% CI: 1.32–2.13) and a lower rate of LGA (OR = 0.51, 95% CI: 0.27–0.96). Interestingly, significant associations of GWG categories in relation to low birth weight (LBW), macrosomia, and SGA were only suggested among pregnant women with MTHFR A1298C AA genotype. Among pregnant women with insufficient GWG group, an increased risk of 3.96 (95% CI: 1.57–10.01) for LBW was observed among subjects with the A1298C AA genotype, compared to the AC+CC genotype group. GWG categories are closely related to LBW, macrosomia, SGA and LGA, and the associations were modified by the polymorphism of MTHFR A1298C.

Preeclampsia, Natural History, Genes, and miRNAs Associated with the Syndrome

Preeclampsia (PE) is a hypertensive disease that affects pregnant women after 20 weeks of gestation. This disease is associated with an important risk of maternal and fetal mortality. PE is described as a placental pathology because, after delivery, most women recover normal arterial pressure. Poor invasion of the spiral arteries is a phenomenon well described in PE; this leads to a hypoxic uterine bed and imbalance of antiangiogenic and proangiogenic factors in the uteroplacental region, which in turn triggers the disease phenotype. The causes of the pathology are unclear; nevertheless, numerous approaches, including next-generation sequencing, association, and case control and miRNA studies, have shed light on the genetic/molecular basis of PE. These studies help us better understand the disease to advance new treatment strategies.

A narrative review on the role of folate-mediated one-carbon metabolism and its associated gene polymorphisms in posing risk to preeclampsia

Preeclampsia (PE) presents a major obstetrical problem for mother and fetus which is characterized by the onset of hypertension and proteinuria in formerly normotensive women. Altered folate-mediated one-carbon metabolism is one of the factors for PE development either due to nutritional insufficiencies such as folate deficiency or polymorphisms in genes that code for the key enzymes of the cycle. Commonly, there are four genes in the cycle whose polymorphisms have been described in relation to PE. These factors could cause elevation of homocysteine; the toxic metabolite, which subsequently leads to the development of PE. Sufficient levels of folate have been considered important during pregnancy and may reduce the risk of development of PE. This review aims at discussing genetic polymorphisms and nutritional deficiencies as probable predisposing factors and suggests considering fetal genotypes, varied ethnicities, and interaction of various other factors involved to render better conclusiveness to the present studies.

The Effect of Interactions between Folic Acid Supplementation and One Carbon Metabolism Gene Variants on Small-for-Gestational-Age Births in the Screening for Pregnancy Endpoints (SCOPE) Cohort Study

Small-for-gestational-age (SGA) is associated with significant perinatal morbidity and mortality. Our aim was to investigate gene-nutrient interactions between maternal one-carbon single nucleotide polymorphisms (SNPs) and folic acid supplement (FAS) use, and their association with SGA. Nulliparous New Zealand women with singleton pregnancy were recruited as part of the Screening for Pregnancy Endpoints prospective cohort study. Data on FAS use was collected via face-to-face interview at 15 weeks’ gestation; participants were followed prospectively and birth outcome data collected within 72 h of delivery. Participants were genotyped for MTHFR 677, MTHFR 1298, MTHFD1 1958, MTR 2756, MTRR 66 and TCN2 776 SNPs. Genotype data for at least one SNP was available for 1873 (93%) of eligible participants. Analysis showed a significant SNP-FAS interaction for MTHFR 1298 (p = 0.020), MTHFR 677 (p = 0.019) and TCN2 776 (p = 0.017) in relation to SGA: MTHFR 1298 CC variant non-FAS users had an increased likelihood [Odds Ratio (OR) = 2.91 (95% Confidence Interval (CI) = 1.52, 5.60] compared with wild-type (MTHFR 1298 AA) FAS users. MTHFR 677 variant allele carrier (MTHFR 677 CT + MTHFR 677 TT) non-FAS users had an increased likelihood [OR = 1.87 (95% CI = 1.21, 2.88)] compared to wild-type (MTHFR 677 CC) FAS users. TCN2 776 variant (TCN2 776 GG) non-FAS users had an increased likelihood [OR = 2.16 (95% CI = 1.26, 3.71)] compared with wild type homozygote + heterozygote (TCN2 776 CC + TCN2 776 CG) FAS users. No significant interactions were observed for MTHFD1 1958, MTR 2756 or MTRR 66 (p > 0.05). We observed an overall pattern of FAS attenuating differences in the likelihood of SGA seen between genotype groups in FAS non-users. Future research should focus on how intake of other one-carbon nutrients might mediate these gene-nutrient interactions.

Polymorphism of MTHFR 1298A>C in relation to adverse pregnancy outcomes in Chinese populations

Background

Adverse pregnancy outcomes (APOs) are involved in a series of abnormal pregnancies like embryo growth arrest, spontaneous abortion, premature birth, stillbirth, fetal malformation, birth defects and other pathological pregnancy, and childbirth complications. Polymorphism of methylenetetrahydrofolate reductase gene (MTHFR, 607093) is one of the main genetic causes of APO. However, there is still debate on whether MTHFR 1298A>C, rs1801131, polymorphism is related to APO. For the lack of extensive research in the Chinese population at present, the study aim to investigate the relationship between MTHFR 1298A>C polymorphism with APO through a large number of data.

Methods

A total of 241 samples from patients with APO and 117 healthy controls in Yunnan province were used for MTHFR gene polymorphism analysis, with double fluorescence quantitative polymerase chain reaction (PCR). In consideration of the low frequency of MTHFR 1298C/C genotype, which might affect the statistic results, further datasets of MTHFR 1298A>C polymorphism were collected from literature and analyzed.

Results

No statistical difference was detected in the frequency of MTHFR1298A>C polymorphism between two groups in Yunnan. Our data showed that the frequency of MTHFR 1298A/A genotype had the decreasing tendency among Chinese population from northern to southern, as well as eastern to western of China. The frequency of MTHFR 1298A/C and 1298C/C genotypes had the adverse tendency. The frequency of MTHFR 1298C/C genotype was significantly different between two groups in Chinese populations. The significant difference was also observed in the frequency of MTHFR 1298C/C polymorphism between two groups from central China and southern China.

Conclusion

In summary, our data showed that MTHFR 1298C/C genotype was one of the important genetic factors of APO in China.

Investigation of potential biomarkers for thrombosis related diseases in Turkish Cypriot population

Genetic and environmental factors are involved in development of many diseases. The allelic frequencies may differ in different populations and in different ethnic groups. The aim of this study was to investigate the genotypes of MTHFR and factor VII polymorphisms and to identify biomarkers for thrombosis related diseases in Turkish Cypriot population. The lipid profiles and genotypes of MTHFR polymorphisms (rs1801133, rs1801131) and factor VII (rs6046) genes were investigated for the first time in the Turkish Cypriot population. The heterozygosity for MTHFR (rs1801133, rs1801131) and FVII (rs6046) polymorphisms is high in Turkish Cypriot population. The heterozygosity for MTHFR C677T was 38%, MTHFR A1298C was 40% and factor VII G353A was 37%, respectively. Allelic frequencies between males and females were similar. There were no correlations between the genotypes of polymorphisms and the lipid profiles. This study is the first genetic epidemiology study that investigated the allelic frequencies of MTHFR and FVII polymorphisms associated with metabolic syndromes. This study proves to be a crucial analysis in order to use these polymorphisms as a predictor of disease development in the Turkish Cypriot community.

Genetic Variants in Preeclampsia: Lessons From Studies in Latin-American Populations

Placental vascularization is a tightly regulated physiological process in which the maternal immune system plays a fundamental role. Vascularization of the maternal-placental interface involves a wide range of mechanisms primarily orchestrated by the fetal extravillous trophoblast and maternal immune cells. In a healthy pregnancy, an immune cross-talk between the mother and fetal cells results in the secretion of immunomodulatory mediators, apoptosis of specific cells, cellular differentiation/proliferation, angiogenesis, and vasculogenesis, altogether favoring a suitable microenvironment for the developing embryo. In the context of vasculopathy underlying common pregnancy disorders, it is believed that inefficient invasion of extravillous trophoblast cells in the endometrium leads to a poor placental blood supply, which, in turn, leads to decreased secretion of angiogenic factors, hypoxia, and inflammation commonly associated with preterm delivery, intrauterine growth restriction, and preeclampsia. In this review, we will focus on studies published by Latin American research groups, providing an extensive review of the role of genetic variants from candidate genes involved in a broad spectrum of biological processes underlying the pathophysiology of preeclampsia. In addition, we will discuss how these studies contribute to fill gaps in the current understanding of preeclampsia. Finally, we discuss some trending topics from important fields associated with pregnancy vascular disorders (e.g., epigenetics, transplantation biology, and non-coding RNAs) and underscore their possible implications in the pathophysiology of preeclampsia. As a result, these efforts are expected to give an overview of the extent of scientific research produced in Latin America and encourage multicentric collaborations by highlighted regional research groups involved in preeclampsia investigation.

Association of Bone Turnover Levels with MTHFR Gene Polymorphisms among Pregnant Women in Wuhan, China

Pregnancy is a critical stimulator of bone mineral resorption. We used to find the MTHFR gene polymorphisms are related with blood lead levels among pregnant women. Pregnancy-stimulated bone turnover may be associated with MTHFR gene polymorphisms too. In this article, we aimed to determine the relationship between MTHFR gene polymorphisms and bone turnover rates among the pregnant women. The participants including pregnant and non-pregnant women were selected and recruited during their routine prenatal or physical examination from July to October in 2012. A total of 1000 participants, including 250 pregnant women in the first, second, and third trimesters and 250 non-pregnant women, were enrolled in the study. Finally, after excluding 27 participants unable to provide blood samples, 973 eligible participants (i.e., 234,249, and 248 pregnant women in the first, second, and third trimesters, respectively, and 242 non-pregnant women) were included in the research. The MTHFR gene 1298CC homozygote carriers were more susceptible to yield higher plasma homocysteine levels than the 1298AA/AC carriers, with standardized coefficients of 0.086 (P<0.05) and 0.104 (P<0.01) of all the participants and the pregnant women, respectively. The MTHFR gene 1793AA homozygote carriers more likely showed higher plasma osteocalcin levels (standardized β=0.091,P<0.01) than the 1793GG/GA carriers among all the subjects. Plasma homocysteine levels were positively correlated with blood lead levels among the participants and the pregnant women with standardized coefficients of 0.320 (P<0.01) and 0.179 (P<0.01), respectively. Plasma osteocalcin levels were positively associated with blood lead levels among pregnant and non-pregnant women with standardized coefficients of 0.084 (P<0.05) and 0.125 (P<0.01), respectively. In conclusion, homocysteine and osteocalcin contents in plasma are associated with the MTHFR gene A1298C polymorphism and blood lead levels among pregnant women. The MTHFR gene A1298C polymorphism-related homocysteine is a possible risk factor for increased blood lead levels among Chinese women.

No evidence for association of MTHFR 677C>T and 1298A>C variants with placental DNA methylation

Background

5,10-Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in one-carbon metabolism that ensures the availability of methyl groups for methylation reactions. Two single-nucleotide polymorphisms (SNPs) in the MTHFR gene, 677C>T and 1298A>C, result in a thermolabile enzyme with reduced function. These variants, in both the maternal and/or fetal genes, have been associated with pregnancy complications including miscarriage, neural tube defects (NTDs), and preeclampsia (PE), perhaps due to altered capacity for DNA methylation (DNAm). In this study, we assessed the association between MTHFR 677TT and 1298CC genotypes and risk of NTDs, PE, or normotensive intrauterine growth restriction (nIUGR). Additionally, we assessed whether these high-risk genotypes are associated with altered DNAm in the placenta.

Results

In 303 placentas screened for this study, we observed no significant association between the occurrence of NTDs (N = 55), PE (early-onset: N = 28, late-onset: N = 20), or nIUGR (N = 21) and placental (fetal) MTHFR 677TT or 1298CC genotypes compared to healthy pregnancies (N = 179), though a trend of increased 677TT genotype in PE/IUGR together was observed (OR 2.53, p = 0.048). DNAm was profiled in 10 high-risk 677 (677TT + 1298AA), 10 high-risk 1298 (677CC + 1298CC), and 10 reference (677CC + 1298AA) genotype placentas. Linear modeling identified no significantly differentially methylated sites between high-risk 677 or 1298 and reference placentas at a false discovery rate < 0.05 and Δβ ≥ 0.05 using the Illumina Infinium HumanMethylation450 BeadChip. Using a differentially methylated region analysis or separating cytosine-guanine dinucleotides (CpGs) by CpG density to reduce multiple comparisons also did not identify differential methylation. Additionally, there was no consistent evidence for altered methylation of repetitive DNA between high-risk and reference placentas.

Conclusions

We conclude that large-scale, genome-wide disruption in DNAm does not occur in placentas with the high-risk MTHFR 677TT or 1298CC genotypes. Furthermore, there was no evidence for an association of the 1298CC genotype and only a tendency to higher 677TT in pregnancy complications of PE/IUGR. This may be due to small sample sizes or folate repletion in our Canadian population attenuating effects of the high-risk MTHFR variants. However, given our results and the conflicting results in the literature, investigations into alternative mechanisms that may explain the link between MTHFR variants and pregnancy complications, or in populations at risk of folate deficiencies, are warranted.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0468-1) contains supplementary material, which is available to authorized users.

Meta-Prediction of MTHFR Gene Polymorphisms and Air Pollution on the Risk of Hypertensive Disorders in Pregnancy Worldwide

Hypertensive disorders in pregnancy (HDP) are devastating health hazards for both women and children. Both methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and air pollution can affect health status and result in increased risk of HDP for women. The major objective of this study was to investigate the effect of MTHFR polymorphisms, air pollution, and their interaction on the risk of HDP by using meta-predictive analytics. We searched various databases comprehensively to access all available studies conducted for various ethnic populations from countries worldwide, from 1997 to 2017. Seventy-one studies with 8064 cases and 13,232 controls for MTHFR C677T and 11 studies with 1425 cases and 1859 controls for MTHFR A1298C were included. MTHFR C677T homozygous TT (risk ratio (RR) = 1.28, p < 0.0001) and CT plus TT (RR = 1.07, p = 0.0002) were the risk genotypes, while wild-type CC played a protective role (RR = 0.94, p = 0.0017) for HDP. The meta-predictive analysis found that the percentage of MTHFR C677T TT plus CT (p = 0.044) and CT (p = 0.043) genotypes in the HDP case group were significantly increased with elevated levels of air pollution worldwide. Additionally, in countries with higher air pollution levels, the pregnant women with wild-type CC MTHFR 677 had a protection effect against HDP (p = 0.014), whereas, the homozygous TT of MTHFR C677T polymorphism was a risk genotype for developing HDP. Air pollution level is an environmental factor interacting with increased MTHFR C677T polymorphisms, impacting the susceptibility of HDP for women.

Genetic variants in 3'-UTRs of MTHFR in the pregnancies complicated with preeclampsia and bioinformatics analysis

Preeclampsia (PE) as a pregnancy-specific disorder is the major cause of mortality and morbidity of mothers and fetuses. This study attempts to investigate the possible association between the 2572C>A (rs4846049) and 4869C>G (rs1537514) polymorphisms in the 3'- untranslated region of MTHFR gene and the risk of PE. A total of 198 patients diagnosed with PE and 171 unrelated, age matched healthy pregnant women, were recruited for this case-control study. The MTHFR 2572C>A and 4869C>G genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The CG genotype of MTHFR 4869C>G was associated with decreased risk of PE, and this genotype was found to be a protective factor for PE susceptibility. There was no significant difference in the genotypes of MTHFR 2572C>A polymorphism between PE patients and control group. The frequency of combined AC/CG genotypes of MTHFR 2572C>A and 4869C>G polymorphisms were less frequent in PE patients and were associated with a lower risk of PE. The C-G and A-G haplotypes of MTHFR 2572C>A and 4869C>G polymorphisms were significantly lower in PE patients. In conclusion, the CG genotype of MTHFR 4869C>G polymorphism was associated with a lower risk of PE. No association was found between MTHFR 2572C>A polymorphism and PE.

The importance of MTHFR C677T/A1298C combined polymorphisms in pulmonary embolism in Turkish population

BACKGROUND AND OBJECTIVE

Pulmonary embolism (PE) is an important cardiovascular emergency with high mortality. There are still problems related to the diagnosis of PE and genetic research may play a key role on diagnosis as well as determining risk stratification. In the present study, the aim was to evaluate MTHFR C677T and A1298C polymorphisms that play a role on folate metabolism in PE patients.

MATERIALS AND METHODS

A total of 118 PE patients and 126 controls were enrolled in the current study. Genomic DNA was isolated and genotyped using polymerase chain reaction (PCR) analyses for the MTHFR C677T and A1298C polymorphisms.

RESULTS

There was no association between clinical and demographic characteristics of PE patients and both MTHFR C677T and A1298C polymorphisms. Allele frequencies showed a significant difference between patients and controls. T allele frequency was significantly higher in the patients' group than the control group. There was an association between PE and combined MTHFR C677T and A1298C polymorphisms.

CONCLUSION

We found an association between MTHFR C677T/A1298C combined mutations and PE in the Turkish population. Future genetic studies investigating combined mutations could be very helpful to identify risk population in PE.

Polymorphisms of the methylenetetrahydrofolate reductase gene (C677T and A1298C) in the placenta of pregnancies complicated with preeclampsia

BACKGROUND

Preeclampsia has been related to single-nucleotide polymorphisms (SNPs) of the methylenetetrahydrofolate reductase (MTHFR) gene; however, data regarding the placenta are still lacking.

OBJECTIVE

To determine the frequency of C677T and A1298C SNPs of the MTHFR gene in the placenta of preeclamptic pregnancies and healthy controls.

METHODS

Genotyping of C677T and A1298C polymorphisms of the MTHFR gene using RFLP-PCR was performed to the placenta of 100 gestations (n = 50 complicated with preeclampsia and n = 50 normal controls matched for parity and maternal age).

RESULTS

Gestational age at birth and neonatal and placental weight were significantly lower in women with preeclampsia as compared to controls. The TT genotype of the C677T polymorphism was threefold more prevalent in preeclamptic placentas as compared to the placenta of controls (24.0% versus 8.0%, p = 0.001). Upon pooled analysis (n = 100), placental and neonatal weights were significantly lower in placentas displaying this genotype (TT, C677T) as compared with the CC genotype.

CONCLUSION

This study found that the frequency of the TT mutant genotype of the C677T polymorphism was higher in the placenta of pregnancies complicated with preeclampsia. There is a need for further research in this matter.

Folate metabolism gene polymorphisms MTHFR C677T and A1298C and risk for preeclampsia: a meta-analysis

OBJECTIVES

MTHFR C677T and A1298C have been associated with the risk of preeclampsia (PE), but with conflicting results. We performed this meta-analysis to derive a more precise estimation of the association between MTHFR polymorphisms and PE.

STUDY DESIGN

An electronic search of PubMed and Chinese Biomedicine database was conducted to select studies for meta-analysis. 54 case controlled studies containing MTHFR C677T and A1298C gene polymorphisms were chosen, and odds ratio (OR) with confidence interval (CI) was used to assess the strength of this association.

RESULT

These studies evaluated 7398 cases and 11230 controls for MTHFR C677T. The overall results suggested that MTHFR C677T was associated with the risk of PE. (T vs. C: OR = 1.157, 95% CI: 1.057-1.266, p = 0.002; TT + CT vs. CC: OR = 1.165, 95% CI : 1.049-1.293, P = 0.004; TT vs. CT + CC: OR = 1.371, 95% CI: 1.153-1.63, p < 0.001). We also evaluated 1103 cases and 988 controls for MTHFR A1298C but could not demonstrate an increased risk of PE for this polymorphism (p = 0.667). A symmetric funnel plot, the Egger's test (p = 0.819) suggested a lack of publication bias.

CONCLUSION

This meta-analysis supports the idea that MTHFR C677T genotype is associated with increased risk for PE, especially in the case of Asians and Caucasians.