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

Abstract

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.     

原因不明复发性流产患者血中亚甲基四氢叶酸还原酶基因C677T和A1298C位点突变的研究

目的　探讨 5 ,10 亚甲基四氢叶酸还原酶基因C6 77T和A12 98C位点突变与原因不明复发性流产 (unexplainedrecurrentspontaneousabortion ,URSA)易感因素的相关性。 方法　采用PCR-限制性片段长度多态性方法 ,检测 14 7例原因不明复发性流产患者 (URSA组 )和 82例有正常妊娠史的妇女 (对照组 )血中亚甲基四氢叶酸还原酶基因C6 77T和A12 98C位点突变。结果　 ( 1)C6 77T的 3种基因型在URSA组和对照组总体分布存在显著性差异 (P =0 0 12 ) ,其中URSA组 :基因型CC占 33 3% ,CT占 5 3 1% ,TT占 13 6 % ,对照组 :基因型CC占 5 2 4 % ,CT占 5 1 5 % ,TT占 6 1%。两组 6 77CC基因表达差异有显著性 (P =0 0 0 5 ) ,URSA组C和T等位基因分别为 4 0 1%、5 9 9% ,两组基因分布情况比较 ,差异有显著性 (P <0 0 0 5 ) ;( 2 )A12 98C的 3种基因型在URSA组和对照组中总体分布情况比较 ,差异无显著性 ,12 98AA/AC/CC基因型和A/C等位基因频率比较 ,差异无显著性 (P >0 0 0 5 ) ;( 3)C6 77T/A12 98C连锁基因分析显示 ,8种连锁基因型中 ,URSA组 6 77CC/ 12 98AA表达频率显著降低 ,而 6 77(CT TT) / 12 98CC仅在URSA组中表达。结论　URSA与亚甲基四氢叶酸还原酶基因C6 77T和A12 98C位点突变有关。     

677 C-->T polymorphism of the methylenetetrahydrofolate reductase gene and preeclampsia

OBJECTIVE: To evaluate C to T substitution at nucleotide 677 of N(5), N(10)-methylenetetrahydrofolate reductase gene in women with prior preeclamptic or normotensive pregnancies. METHODS: Methylenetetrahydrofolate reductase genotypes were determined in 113 Finnish women with preeclamptic first pregnancies and 103 controls with one or more normotensive pregnancies, using polymerase chain reaction and restriction enzyme analysis. Preeclampsia was defined as severe in 100 women who fulfilled one or more of the subsequent criteria: systolic blood pressure (BP) at least 160 mmHg, diastolic BP at least 110 mmHg, or proteinuria at least 2 g per 24-hour urine collection. RESULTS: There were no significant differences in prevalences of the methylenetetrahydrofolate reductase genotypes (CC, CT, and TT) between groups (57%, 40%, and 3% in the preeclamptic group and 54%, 39%, and 7%, respectively, in controls). The frequency of the T677 allele was 0.23 in the preeclamptic group and 0.26 in the control group (difference 0.03; 95% confidence interval -0.08, 0.14; P =.51). Our sample had 60% power to detect a difference of the allele frequencies similar to that (0.12) reported previously. The result was similar when analysis was restricted to patients with severe preeclampsia (T677 allele frequency 0.22). CONCLUSION: A carrier status for the T677 allele of the methylenetetrahydrofolate reductase gene does not predispose to preeclampsia, at least in the Finnish population.     

Association of methylenetetrahydrofolate reductase C677T polymorphism with the pre-eclampsia risk in Hakka pregnant women in Southern China

Abstract

The aim of this study is to clarify the possible association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and pre-eclampsia in Hakka pregnant women in southern China. Pre-eclampsia and normal pregnant women were consecutively collected and MTHFR C677T genotypes were determined by the DNA sequencing method. One hundred and thirteen pre-eclampsia patients were CC homozygote (113 of 191, 59.2%), 68 of 191 (35.6%) were CT heterozygote, and 10 of 191 (5.2%) were TT homozygote, with the frequency of the T allele equal to 0.77. This is in comparison with the normal control group where 106 of 202 (52.5%) were CC homozygote, 83 of 202 (41.1%) were CT heterozygote, and 13 of 202 (6.4%) were TT homozygote, with the frequency of the T allele equal to 0.27. No statistically significant differences were observed in genotype or allele frequencies between the pre-eclampsia and normal control for the C677T polymorphism of MTHFR gene (p?>?.05). The findings of this study suggest that polymorphisms of MTHFR C677T genes were not associated with pre-eclampsia in Hakka pregnant women from southern China, but additional studies are necessary to explore the mechanisms involving it.     

ACL(+)复发性流产与亚甲基四氢叶酸还原酶C677T和A1298C位点突变关联的研究

目的:探讨亚甲基四氢叶酸还原酶基因(methylenetetrahydrofolate reductase,MTHFR)C677T和A1298C位点突变与抗心磷脂抗体(anticard iolipin antibody,ACL)阳性复发性流产是否相关。方法:采用聚合酶链式反应-限制性片断长度多态性方法,检测39例原因不明复发性流产和82例正常对照的亚甲基四氢叶酸还原酶基因C677T和A1298C位点突变。结果:MTHFR 677 3种基因型(CC、CT和TT)在ACL(+)流产组和对照组分布有统计学差异(P=0.045),进一步分析表明,677TT在患者组中表达频率显著增大(P=0.026),T等位基因频率在患者组中也显著增大(P=0.018),MTHFR1298相关3种基因型(AA、AC和CC)和A、C等位基因频率在2组中分布无差异,同时发现8种C677T/A1298C连锁基因型,但都与ACL(+)复发性流产无关。结论:ACL(+)复发性流产与MTHFR C677T突变有关,表明除自身抗体有关的获得性凝血途径以外,遗传性凝血因素在此种类型的流产发生中也起一定的作用。     

思南县女性5,10-亚甲基四氢叶酸还原酶基因多态性调查及其与血清同型半胱氨酸水平相关性的研究

目的:研究叶酸代谢障碍关键酶基因5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C位点基因多态性与血清同型半胱氨酸(HCY)的相关性。方法:随机以贵州省思南县2 188例女性为研究对象,检测其MTHFR C677T、A1298C基因位点多态性,采用统计学方法分析该地区基因的多态性分布特征,并与其他同等级区域人群既有数据比对分析;对其中276例孕期女性,测定血清HCY浓度,分析该指标与遗传因素的相关性。结果:本县的汉族、苗族、土家族女性MTHFR C677T、A1298C位点基因型及等位基因分布情况差异无统计学意义(P0.05)。本地区汉族女性MTHFR 677TT基因型频率(14.9%)显著低于尚志、三河、寿光、张家港等地人群(P0.05),显著高于陵水县人群(P0.05);与郫县人群数据差异无统计学意义(P0.05)。MTHFR 1298CC基因型频率(4.2%)与郫县人群无统计学差异(P0.05),与其他各地区人群均有统计学差异(P0.05)。血清HCY水平在C677T位点3种基因型间有统计学差异(P0.05),而A1298C位点3种基因型间无统计学差异(P0.05)。结论:本县汉族女性MTHFR基因C677T、A1298C位点多态性分布特征有其自身的特点;C677T位点的多态性变化对血清HCY水平有显著影响。     

Ethnic differences in the association of factor V Leiden mutation and the C677T methylenetetrahydrofolate reductase gene polymorphism with preeclampsia

OBJECTIVE: This case-control study evaluates the association of the factor V Leiden mutation with preeclampsia and potential synergistic effects of the MTHFR-677T and factor V Leiden mutations with regard to disease risk in two different ethnic populations. STUDY DESIGN: 198 women and their 143 newborns from Germany/Croatia and Indonesia with normal pregnancy or preeclampsia participated in the study. The factor V Leiden mutation was determined by direct sequencing and the MTHFR genotype by a PCR-based RFLP method. RESULTS: The factor V Leiden mutation is rare in Indonesians. In Germans/Croatians, the frequency of the mutation was significantly increased in mothers with preeclampsia compared to controls. No disease association was found for combined factor V Leiden/MTHFR-677T genotypes on the maternal and fetal level. CONCLUSIONS: Our results underline the need for a clear distinction of ethnicity in association studies of functional gene polymorphisms. They further support the concept of preeclampsia as a complex disease with variable contributions of disease genes in different ethnic groups.     

The C677T polymorphism of the methylenetetrahydrofolate reductase gene and idiopathic recurrent miscarriage

OBJECTIVE:To investigate the association between the C677T polymorphism of the 5,10-methylenetetrahydrofolate reductase gene (MTHFR), serum homocysteine levels, and idiopathic recurrent miscarriage in a Middle-European white population.METHODS:In a case control study, we investigated 133 women with a history of three or more consecutive pregnancy losses before 20 weeks' gestation and 74 healthy controls with at least two live births and no history of pregnancy loss. A DNA extraction and polymerase chain reaction followed by restriction fragment length polymorphism analysis were used to genotype women for the presence of the MTHFR C677T polymorphism. Serum homocysteine levels were assessed by a fluorescence polarization immunoassay.RESULTS:The MTHFR allele frequencies in women with idiopathic recurrent miscarriage and controls were 34.6% and 21.6%, respectively, for the T allele (mutant) and 65.4% and 78.4%, respectively, for the C allele (wild type) (P =.007, odds ratio 1.9, 95% confidence interval 1.2, 3.1). The MTHFR genotype frequencies in women with idiopathic recurrent miscarriage and controls were: 17.3% (T/T), 34.6% (C/T), 48.1% (C/C) and 5.4% (T/T), 32.4% (C/T), 62.2% (C/C), respectively (P =.03, odds ratio 3.7, 95% confidence interval 1.2, 11.8 [T/T versus C/T and C/C]). Serum concentrations of homocysteine were significantly higher in carriers of a MTHFR mutant allele compared with women with no mutant allele (mean 7.4 +/- 2.4 micromol/L [T/T + C/T] versus 6.5 +/- 2.6 micromol/L [C/C], P =.05).CONCLUSION:Carriage of the mutant allele of the MTHFR C677T polymorphism is associated with elevated serum levels of homocysteine and idiopathic recurrent miscarriage.     

Combined heterozygosity for methylenetetrahydrofolate reductase (MTHFR) mutations C677T and A1298C is associated with abruptio placentae but not with intrauterine growth restriction.

OBJECTIVE: This study was undertaken to investigate the involvement of MTHFR gene mutations C677T and A1298C implicated in vascular disease, in patients with abruptio placentae and intrauterine growth restriction (IUGR). STUDY DESIGN: DNA was extracted from blood samples of 54 patients with placental vasculopathy (18 patients with abruptio placentae and 36 with IUGR) and 114 control patients and amplified by the polymerase chain reaction (PCR). The resulting fragments were subjected to restriction enzyme analysis and resolved by gel electrophoresis. RESULTS: A significant association could be demonstrated between mutation A1298C and both abruptio placentae and IUGR. Combined heterozygosity for mutations C677T and A1298C was detected in 22.2% of abruptio placentae cases. CONCLUSIONS: Combined heterozygosity for MTHFR mutations C677T and A1298C may represent a genetic marker for abruptio placentae.     

The methylenetetrahydrofolate reductase 677 C-->T polymorphism and preeclampsia in two populations

OBJECTIVE: The C677T polymorphism of the 5,10 methylenetetrahydrofolate reductase (MTHFR) gene is associated with decreased MTHFR activity and elevated plasma homocysteine levels with the result of an increased risk for vascular disease. Because thrombosis of the maternal spiral arteries can be one of the causative events in the disease, it has been suggested that the C677T polymorphism may also play a role in the pathogenesis of preeclampsia. Our case-control study investigated the prevalence of the 677T allele in two ethnically different populations and the potential association of the 677T allele with preeclampsia. Special attention was paid to the potential contribution of the fetal genotype to disease risk. METHODS: Blood samples were collected from 81 mothers and 61 newborns after preeclampsia and 99 mothers and 61 newborns with normal pregnancies. Genomic DNA was amplified by polymerase chain reaction with locus-specific primers, and presence of the polymorphism was determined by enzymatic digestion with HinfI and visualization on polyacrylamide gels. RESULTS: Genotypes carrying the MTHFR 677T allele were significantly more frequent in German-Croatians than in Indonesians in both patients and controls (P =.0033 in controls). In contrast, the prevalence of genotypes with the 677T allele was not increased among patients with preeclampsia compared with controls in both ethnic groups (P >.5 in all groups). In Germans, the frequency of 677T homozygotes among controls even exceeded that observed in preeclamptic patients (677T/T genotype frequency 0.20 in controls and 0.07 in patients). We did not find an increased prevalence of paternally inherited 677T alleles in preeclamptic fetuses relative to controls or other signs of maternal-fetal transmission distortion. CONCLUSION: In our study, the MTHFR C677T polymorphism was not associated with an increased risk for preeclampsia on the level of the maternal or fetal genotype. However, significant differences of the frequency of genotypes carrying the 677T allele between Middle-Europeans and Indonesians were identified.     

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.     

Fetal folate C677T methylenetetrahydrofolate reductase gene polymorphism and low birth weight.

The aim of this study was to determine if fetal C677T methylenetetrahydrofolate reductase (MTHFR) genotype contributes to low birth weight. The study group consisted of 243 term babies with a birth weight<10th centile for gestational age, with subgroup analyses for those <1st centile. The control group consisted of 132 term babies with a birth weight 3.3-3.8 kg. Odds ratio analyses with 95% confidence intervals (CI) were calculated for carriage of the t allele and overall genotype frequencies. There was no significant difference in carriage of the t allele between study and control groups, odds ratio (OR) 0.79 (95% CI, 0.57-1.09). No differences were observed for frequencies of heterozygote and recessive homozygote genotypes for the two populations. In the subgroup analyses, no statistical differences were observed in the t allele frequency, frequency of the heterozygote or homozygote genotype. Trends were seen and the study suggests that fetal C677T MTHFR genotype may be a factor contributing to birth weight. The potential may exist to influence clinical outcome by maternal folate supplementation.     

Association of the C677T methylenetetrahydrofolate reductase mutation with congenital heart diseases

BACKGROUND: To investigate whether the cytosine-to-thymine mutation at base 677 of the gene for methylenetetrahydrofolate reductase (MTHFR) is associated with congenital heart diseases (CHD), using high throughput heteroduplex analysis based upon the powerful technique of denaturing high-performance liquid chromatography. METHODS: We investigated the MTHFR genotype of a cytosine-to-thymine mutation at base 677 for 213 patients of CHDs as confirmed by cardiac catheterization and also for 195 healthy controls. RESULTS: The overall genotype frequencies of the MTHFR C677T polymorphism were not significantly different between the CHD patients and the healthy control (P = 0.345). Furthermore, taking various subgroups of CHD patients into consideration, we noted a significantly increased proportion of homozygous TT genotypes for patients suffering from valvular pulmonary stenosis (PS) or pulmonary atresia with an intact ventricular septum (PA + IVS) (p = 0.0005). For patients revealing heterotaxy syndrome, a conotruncal anomaly including tetralogy of Fallot, an interruption of the aortic arch, persistent truncus arteriosus, and aortopulmonary window, no statistically significant difference existed. CONCLUSIONS: The discrepancy in the distribution of MTHFR genotypes amongst various subtypes of CHD reflects some heterogeneity in the developmental mechanism of CHD. The increased percentage of homozygous TT genotypes might contribute to the pathogenesis of valvular PS and PA + IVS.     

History of abortion and perinatal outcomes associated with preeclampsia in nulliparous Japanese women

The purpose of the present study was to examine the influence of history of abortion on the next pregnancy outcomes associated with preeclampsia. This investigation involved 5206 nulliparous Japanese women with singleton pregnancies who delivered after 22 weeks of gestation. The patients were divided into two groups: those with a history of spontaneous and/or artificial abortion during the previous pregnancies after the marriage with the same partner (n?=?1029) and those without a history of abortion (n?=?4173). There was no significant difference in the incidence of preeclampsia between the 2 groups with and without previous abortions (4.0% vs. 3.9%, p?=?0.91). In addition, there were no significant differences in the incidence of perinatal complications associated with preeclampsia between the 2 groups. Although further studies may be needed, based on the current results history of abortion does not seem to affect perinatal outcomes associated with preeclampsia.     

Association of congenital cardiac defects and the C677T methylenetetrahydrofolate reductase polymorphism

OBJECTIVE: MTHFR C677T polymorphism and hyperhomocysteinemia have been associated with congenital malformations of the heart and neural tube defects. A common missense mutation in the MTHFR gene (C to T substitution at position 677) produces a variant with reduced enzymatic action.The aim of this retrospective case control study was to investigate whether the occurrence of the MTHFR polymorphism is increased in mothers and fathers of children with a congenital heart disease (CHD) in our population. METHODS: We genotyped 31 couples with CHD offspring and 31 control couples for this study by obtaining smears from buccal gingiva cells and analyzed these for the MTHFR polymorphism by hybridization on microarrays. RESULTS: Statistical significance was calculated using the chi-square test and Pearson-exact test, respectively. The prevalence of homozygosity or heterozygosity for the MTHFR polymorphism was not significantly increased in parents of CHD affected children. Nevertheless significance was observed for the association between aortic arch anomalies and the mothers. CONCLUSIONS: The results of this study do not show any significant association between the MTHFR C677T polymorphism and CHD in our population. Although the numbers are small (n = 3), the MTHFR (C677T) polymorphism may be linked to the development of aortic arch anomalies.     

Visfatin serum levels are increased in women with preeclampsia: A case-control study

Objective: Visfatin has been implicated in the pathogenesis of preeclampsia with limited and contradictory, however, results. The aim of this study was to investigate the potential association between visfatin serum concentration and preeclampsia. Methods: Visfatin was determined in the serum of 38 women with preeclampsia and 38 women with uncomplicated pregnancies, matched for age and gestational age. Results: Similar baseline characteristics were present between the two groups in terms of age, body mass index, parity and gravidity. Serum visfatin was significantly increased in the preeclamptic women (median?=?10.3?ng/mL; interquartile range [IQR]?=?20) as opposed to their matched controls (median?=?2.6?ng/mL; IQR?=?1.4) (p?<?0.001). Univariate analysis revealed a strong linear correlation of visfatin levels with systolic (r?=?0.505, p?<?0.001), diastolic (r?=?0.467, p?<?0.001) and mean arterial blood pressure (r?=?0.497, p?<?0.001), as well as with uric acid concentrations in the serum (r?=?0.463, p?<?0.001). A receiver operating characteristics curve analysis illustrated that serum visfatin concentration is helpful in discriminating between preeclamptic or nonpreeclamptic women with an area under the curve of 0.887 (95% confidence interval [CI]: 0.794–0.948; p?<?0.001). Conclusion: Visfatin serum concentration seems to be increased in preeclampsia as compared with uncomplicated pregnancy.