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.     

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.     

The C46T polymorphism of the coagulation factor XII gene and idiopathic recurrent miscarriage

Thrombophilia has been described to be involved in the pathogenesis of idiopathic recurrent miscarriage (IRM). We investigated the association between IRM and a C-->T polymorphism at nucleotide 46 in the 5'-untranslated region of the coagulation factor XII (FXII) gene. Two hundred and twelve women with a history of IRM and 149 healthy controls were tested by a mutagenically separated polymerase chain reaction assay (MS PCR). Allele and genotype frequencies were not significantly different between the study and the control groups. Our data suggest that the FXII gene is not a candidate gene for this condition.     

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.     

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。     

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。     

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.     

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 PROGINS progesterone receptor gene polymorphism and idiopathic recurrent miscarriage.

OBJECTIVE: Progesterone inhibits lymphocyte cytotoxicity, natural killer cell degranulation, and release of proinflammatory cytokines and has been shown to protect against spontaneous miscarriage. We investigated the association between idiopathic recurrent miscarriage (IRM) and the PROGINS 306 base pair insertion polymorphism in intron G of the progesterone receptor gene, which is known to segregate with progesterone-dependent neoplasms. METHODS: In a case-control study we investigated 125 women with a history of three or more consecutive pregnancy losses before 20 weeks' gestation and 79 healthy controls with at least two live births and no history of pregnancy loss. Peripheral venous puncture, DNA extraction, and polymerase chain reaction were used to genotype women for the presence of the PROGINS polymorphism. RESULTS: Allele frequencies among women with IRM and controls were 85.2% and 89.2%, respectively, for allele T1 (wild type) and 14.8% and 10.8%, respectively, for allele T2 (mutant). No association between allele T2 and the occurrence of IRM was found (P =.3; odds ratio [OR] 0.69; confidence interval [CI] 0.34, 1.40). Genotype frequencies were not significantly different between the study group (T1/T1 73.6%, T1/T2 23.2%, T2/T2 3.2%) and the control group (T1/T1 79.7%, T1/T2 19%, T2/T2 1.3%) (P =.4). Between women with primary and secondary IRM, there were no statistically significant differences with respect to allele frequencies (82% versus 87%, P =.4 for allele T1 and 12% versus 13%, P =.6 for allele T2). CONCLUSIONS: We found that the PROGINS polymorphism in the progesterone receptor gene was not associated with IRM in white women.     

Tryptophan hydroxylase gene polymorphism (A218C) and idiopathic recurrent miscarriage

OBJECTIVE: To investigate the frequency of a polymorphism in intron 7 of the tryptophan hydroxylase gene among women with idiopathic recurrent miscarriage and healthy controls. METHODS: In a case control study, we studied 125 women with a history of three or more consecutive pregnancy losses before 20 weeks' gestation and 137 healthy controls with at least two live births and no history of pregnancy loss. Peripheral venous puncture, DNA extraction, and polymerase chain reaction followed by restriction fragment length polymorphism analysis were used to genotype women for the presence of the A218C polymorphism in intron 7 of the tryptophan hydroxylase gene. RESULTS: Allele frequencies among women with idiopathic recurrent miscarriage and controls were 32.4% and 38.7%, respectively, for allele A (wild type) and 67.6% and 61.3%, respectively, for allele C (mutant). No association between the presence of allele C and idiopathic recurrent miscarriage was found (P = .3; odds ratio 1.31; 95% confidence interval 0.93, 1.87). Genotype frequencies also were not significantly different between the study group (C/C: 44.8%; A/C: 45.6%; A/A: 9.6%) and the control group (C/C: 37.2%; A/C: 48.2%; A/A: 14.6%; P = .2). Between women with primary and women with secondary idiopathic recurrent miscarriage, no statistically significant differences with respect to allele frequencies were observed (63% vs 62% for allele C and 31% vs 38% for allele A; P = .3). CONCLUSION: The A218C polymorphism in intron 7 of the tryptophan hydroxylase gene is not associated with idiopathic recurrent miscarriage.     

A polymorphism of the interleukin-1beta gene and idiopathic recurrent miscarriage

OBJECTIVE: Proinflammatory cytokines have been described to be involved in the pathogenesis of idiopathic recurrent miscarriage (IRM). We investigated the association between IRM and a polymorphism in exon 5 of the interleukin-1beta gene (IL1B) and interleukin-1beta (IL-1beta) serum levels. DESIGN: Case control study. SETTING: Academic research institution. SUBJECTS: One hundred thirty-one women with a history of three or more consecutive pregnancy losses before 20 weeks' gestation and 68 healthy controls with at least two live births and no history of pregnancy loss. INTERVENTIONS: Peripheral venous puncture. MAIN OUTCOME MEASURES: An IL1B exon 5 (position +3953) gene polymorphism was analyzed by PCR amplification followed by restriction fragment length polymorphism analysis. IL-1beta serum levels were analyzed by a commercially available ELISA. RESULTS: Allele frequencies in women with IRM and controls were 77.9% and 80.8%, respectively, for the E1 allele (wild type), and 22.1% and 19.2%, respectively, for the E2 allele (mutant). No association between the E2 allele and the occurrence of IRM was found (P=.57, odds ratio =.83). Genotype frequencies and IL-1beta serum levels were not significantly different between the study group and the control group. CONCLUSIONS: This is the first report on an IL1B polymorphism in IRM. Although known to alter IL-1beta expression, the investigated IL1B polymorphism is not associated with IRM and increased serum levels in a large Caucasian population.     

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.     

C677T methylenetetrahydrofolate reductase polymorphism interferes with the effects of folic acid and zinc sulfate on sperm concentration

OBJECTIVE: To determine the frequency of C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism in fertile and subfertile males, and the MTHFR-dependent response of sperm concentration after folic acid and/or zinc sulfate intervention. DESIGN: Double-blind, placebo-controlled intervention study.Two outpatient fertility clinics and nine midwifery practices in The Netherlands. PATIENT(S): One hundred thirteen fertile and 77 subfertile males.Daily capsules of folic acid (5 mg) and/or zinc sulfate (66 mg), or placebo for 26 weeks. MAIN OUTCOME MEASURE(S): Prevalence of C677T MTHFR polymorphism and the response of sperm concentration related to MTHFR carriership after intervention treatment. RESULT(S): The C677T methylenetetrahydrofolate reductase genotypes were comparable in fertile and subfertile males. Independent of fertility state, sperm concentration significantly increased in wild-types after folic acid and zinc sulfate treatment only. Heterozygotes and homozygotes did not significantly benefit from either treatment. CONCLUSION(S):C677T methylenetetrahydrofolate reductase polymorphism is not a risk factor for male factor subfertility. In contrast to heterozygotes and homozygotes for C677T MTHFR polymorphism, sperm concentration in wild-types significantly improved after folic acid and zinc sulfate intervention. A stronger role of other folate genes on spermatogenesis is suggested.     

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.     

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

Objective: To determine the prevalence of C677T and A1298C Single-nucleotide polymorphisms (SNPs) of the MTHFR gene in nulliparous women complicated with preeclampsia (PE).

Methods: One hundred fifty gestations complicated with PE and their corresponding controls without the disease were recruited for the genotyping of C677T and A1298C polymorphisms of the MTHFR gene using restriction fragment length polymorphism polymerase chain reaction. Secondarily, homocysteine (HCy) plasma levels were measured in preeclamptic women displaying the CC genotype of the A1298C polymorphism (homozygous) and compared to HCy levels determined among controls with the normal AA genotype for the A1298C variant.

Results: Only the mutant CC genotype of the A1298C polymorphism was associated to higher risk of presenting PE, as frequency of this genotype was significantly higher among cases than controls (15.3% versus 0.7%, p?p?=?0.0001). Women with the mutant CC A1298C SNP displayed higher plasma HCy levels as compared to controls with normal AA A1298C genotype (8.4?±?2.6 versus 7.5?±?2.7?mmoL/L p?=?0.04).

Conclusion: Prevalence of the CC mutant genotype of the A1298C polymorphism was higher among PE women. This mutation among PE women was related to increased neck circumference and higher HCy levels. Future research should aim at linking these gestational findings with obesity and cardiovascular risk.     

亚甲基四氢叶酸还原酶基因C677T单核苷酸多态性与卵巢癌易感性的关系

目的:研究亚甲基四氢叶酸还原酶(MTHFR)基因第4外显子677位点单核苷酸多态性与卵巢癌易感性的关系。方法:采用聚合酶链反应-限制性片段长度多态性方法,检测81例卵巢癌患者和80例正常对照者的亚甲基四氢叶酸还原酶基因C677T位点突变。结果:卵巢癌组和对照组中MTHFR基因677等位基因位点C和T的分布差异有统计学意义(P<0.05),其中等位基因T使卵巢癌发病风险增加1.93倍。MTHFR基因677C/T各基因型分布差异有统计学意义(P<0.05),纯合突变(T/T)基因型、杂合突变(C/T)基因型与野生(C/C)基因型相比,患卵巢癌的危险度分别提高了3.48倍和2.15倍。结论:MTHFR基因677位点等位基因突变与卵巢癌发生有一定关系,突变基因型增加了卵巢癌的发病风险。     

Prevalent genotypes of methylenetetrahydrofolate reductase (MTHFR) in recurrent miscarriage and recurrent implantation failure

Objective

To evaluate the association of two common methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms with recurrent miscarriage (RM) and repeated implantation failure (RIF)

Methods

The study comprised of 521 patients, with a history of RM (n?=?370) or RIF (n?=?151). One hundred forty-four women with fallopian tube blockages who had successfully conceived after the first in vitro fertilization embryo transfer treatment served as the control group. The MTHFR alleles, genotypes, and haplotypes were assessed in different groups.

Results

There was no difference in allele frequency and distribution of MTHFR polymorphisms between case and control patients. The 1298AA genotype was represented in a higher frequency, and 1298AC genotype was significantly lower in subfertile group when compared to the control group. A significant relationship was found between the 1298AC genotype and the RIF subgroup. The haplotype 677CC/1298AA was overrepresented in the RM subgroup (>?2 times) and haplotype 677CC/1298AC was underrepresented in the RIF subgroup (P?<?0.05). Nevertheless, these two haplotypes were not connected to fertilization and embryo cleavage rates.

Conclusion

Our findings indicate that the MTHFR gene polymorphism might play a role in the etiology of patients with RM or RIF. No adverse effects of different MTHFR haplotypes on embryo development were detected. Further studies on the biological role are needed to better understand the susceptibility to pregnancy complications.