MTHFR、MTRR基因多态性与反复流产的相关性分析

目的探讨叶酸代谢相关基因5,10-亚甲基四氢叶酸还原酶(MTHFR)、甲硫氨酸合成酶还原酶(MTRR)多态性与反复流产的关系,分析基因多态性对红细胞叶酸水平的影响。方法选取2016年12月至2018年6月来唐山市妇幼保健院遗传咨询门诊,要求进行常规孕前检查,汉族非妊娠健康女性424例为研究对象。依据不良孕产史分为两组,其中病例组216例和对照组218例。采集静脉血,提取DNA,荧光定量PCR法进行MTHFR、MTRR基因多态性检测。化学发光法进行红细胞叶酸定量检测。采用SPSS19.0软件进行统计学分析。比较两组MTHFR、MTRR基因多态性分布频率、不同基因类型红细胞叶酸水平。探讨基因多态性、红细胞叶酸水平与反复流产的关系。结果MTHFR A1298C和MTRR A66G两位点多态性在病例组和对照组间的分布,差异无统计学意义。MTHFR C677T位点多态性,在病例组中的分布频率明显高于对照组,差异具有统计学意义。病例组中MTHFR C667T位点TT型基因突变的患者红细胞叶酸水平远低于正常和杂合型。结论MTHFR C677T基因突变与反复流产的密切相关,MTHFR C667T位点TT型基因突变影响机体红细胞叶酸代谢水平。     

同型半胱氨酸代谢酶基因突变多态性与妊娠高血压综合征遗传易感性研究

目的探讨同型半胱氨酸代谢酶—甲基四氢叶酸还原酶(MTHFR)、蛋氨酸合成酶(MS)和胱硫醚-β合成酶(CBβS)基因多态性在妊娠高血压综合征(妊高征)发病中的作用地位。方法荧光偏振免疫分析法测定血浆总Hcy浓度;聚合酶链反应-限制性片段长度多态性技术(PCR-RFLP)检测MTHFRC677T、MSA2756G、MTRRA66G和CBβS844ins68基因多态性。结果病例组MTHFRC677TC/T基因型频率显著高于正常对照组,总的突变T等位基因频率显著高于对照组(P<0.05);病例组MS野生型A等位基因频率明显高于对照组,而突变型G等位基因频率显著低于对照组。结论MTHFRC677T基因突变是妊高征发生的遗传风险因素;MSA2756多态性改变是妊高征的保护因子。二者均可作为妊高征预后的检测指标。     

血浆Hcy水平及MTHFR和MTRR基因多态性与复发性流产的相关性研究

目的探讨血清同型半胱氨酸(Hcy)水平及亚甲基四氢叶酸还原酶(MTHFR)、甲硫氨酸合成酶还原酶(MTRR)基因多态性与不明原因复发性流产的相关性。方法以84例复发性自然流产的患者作为病例组,60例已有1次正常生育史,且既往无不良孕产史的妇女作为对照组,应用荧光定量PCR技术检测MTHFR基因C677T、A1298C和MTRR A66G位点的多态性,同时应用比色法检测血清Hcy水平。比较病例组和对照组间各种基因型和血清Hcy水平的差异。结果病例组血清Hcy水平明显高于对照组;高Hcy是先兆流产的危险因素(OR=2.132,P=0.021);MTHFR C677位点TT基因型携带者血清Hcy水平明显高于其他基因型;A1298位点CC基因型携带者血清Hcy水平明显高于AA野生型;MTRR A66位点GG基因型携带者血清Hcy水平明显高于其他基因型,差异均有统计学意义(P0.05)。结论 Hcy升高是导致复发性流产的重要危险因素;MTHFR基因C677T、A1298C和MTRR A66G位点的多态性改变均可致血清Hcy水平升高,与复发性流产的发生有一定的相关性。     

洛阳地区不明原因复发性流产女性MTHFR基因C677T位点多态性分析

目的通过研究洛阳地区不明原因复发性流产女性患者亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点多态性分布情况,探索其与不明原因复发性流产(URSA)的关系。方法采用荧光定量PCR方法对109例URSA女性患者和487例健康经产妇MTHFR基因C677T位点进行检测,对比两组女性的等位基因分布频率,分析其多态性与URSA的关系。结果 URSA组MTHFR基因C677T位点T/T型分布频率明显高于对照组,差异具有统计学意义(P0.05);T/T型女性发生URSA的危险性增加(OR=1.942,95%CI:1.012～3.726)。结论洛阳地区女性不明原因复发性流产与MTHFR基因C677T位点多态性相关。     

同型半胱氨酸代谢酶基因多态性与深静脉血栓的相关性研究

目的探讨亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase，MTHFR）基因C677T、甲硫氨酸合成酶（methionine synthase，MS）基因A2756G和胱硫醚β-合成酶（cystathionine β-synthase，CBS）基因844ins68这3种基因突变在深静脉血栓发病中的意义。方法应用聚合酶链反应-限制性片段长度多态性方法对103例深静脉血栓患者和250名健康对照者进行MTHFR C677T、MS A2756G和CBS 844ins68基因多态性的分析，并进行基因型及等位基因频率的计数。对MTHFR C677T和MS A2756G两位点进行单倍型分析。结果MTHFR C677T TT基因型在深静脉血栓组的分布频率（27．2％）高于对照组（17．2％），经χ^2检验差异有统计学意义（P〈0．05）。MS A2756G AG基因型在深静脉血栓组的分布频率（9．7％）低于对照组（19．2％），经χ^2检验差异有统计学意义（P〈0．05）。单倍型分析显示病例组中677T-2756A单倍型频率明显高于对照组（P〈0．05），677C-2756A单倍型频率明显低于对照组（P〈0．05）。CBS 844ins68基因型在两组的分布频率差异无统计学意义。结论MTHFR C677T多态性中TT基因型可能是深静脉血栓形成的一个遗传风险因子，MS 2756 AG基因型可能会减少深静脉血栓的发生。677T-2756A单倍型可能是静脉血栓的危险因素，677C-2756A单倍型可能是静脉血栓的保护因素。CBS 844ins68基因突变可能存在种族或地域的差异。     

叶酸代谢酶MTHFR基因多态性与不明原因复发性流产的相关性研究

目的初步探讨亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C位点单核苷酸多态性与苏南地区不明原因的复发性流产(URSA)发生的相关性。方法采用病例对照研究的方法,对170例苏南地区不明原因复发性流产者(病例组)和170例正常妇女(对照组),利用PCR荧光探针技术检测MTHFR基因C677T、A1298C位点的单核苷酸多态性。结果病例组MTHFRC677T位点的TT基因型的发生频率显著高于对照组,T等位基因频率同样高于对照组,差异均有统计学意义(P0.05),而病例组MTHFR基因A1298C位点的CC基因型频率和C等位基因频率与对照组的相比,差异均无统计学意义(P0.05)。结论苏南地区MTHFR基因C677T位点多态性与育龄妇女发生不明原因复发性流产有一定的相关性。     

孕期妇女MTHFR、MTRR基因多态性与同型半胱氨酸水平的关系

目的分析甘肃省孕期妇女N5,10-亚甲基四氢叶酸还原酶(N5,10-methylenetetrahydrofolate reductase,MTHFR)C677T、A1298C及甲硫氨酸合成酶还原酶(5-methyltetrahydrofolate-homocysteine methyltransferasereductase,MTRR)A66G位点基因多态性的分布特点,并研究其多态性与血浆同型半胱氨酸(Homocysteine,Hcy)浓度的相关性,为孕期妇女补服叶酸提供理论依据。方法以2016年在甘肃省妇幼保健院做孕期检查的522例孕妇为研究对象,检测MTHFR基因C677T、A1298C和MTRR基因A66G位点的基因型,并测定血浆Hcy浓度,应用t检验与Spearman秩检验比较不同基因型间Hcy浓度的差异。结果 MTHFR基因C677T位点CC型、CT型与TT型分别占26.83%、45.12%、28.05%,A1298C位点AA型、AC型、CC型分别占68.29%、26.83%、4.88%。MTRR基因A66G位点AA型、AG型与GG型分别占53.66%、39.02%、7.32%。MTHFR基因C677T位点等位基因C占49.39%,等位基因T占50.61%,A1298C位点等位基因A占81.71%,C占18.29%。MTRR基因A66G位点等位基因A占73.17%,等位基因G占26.83%。MTHFR基因C677T位点CC型、CT型与TT型Hcy含量分布经两两t检验,P0.05,说明各基因型间Hcy分布差异均有统计学意义。MTHFR基因A1298C位点AA型、AC型、CC型,MTRR基因A66G位点AA型、AG型与GG型Hcy含量分布经两两t检验,P0.05,说明各基因型间Hcy分布差异无统计学意义。MTHFR基因C677T、A1298C和MTRR基因A66G位点多态性各风险组经两两t检验,与未发现风险组比较,低度风险组、中度风险组、高度风险组P均小于0.05,差异具有统计学意义;与低度风险组比较,中度风险组、高度风险组P均大于0.05,差异没有统计学意义;与中度风险组比较,高度风险组P小于0.05,差异有统计学意义。根据Spearman秩相关检验,P0.05,Hcy含量与风险等级具有显著相关性。结论 MTHFR基因C677T、A1298C和MTRR基因A66G位点存在基因多态性,MTHFR基因C677T、A1298C和MTRR基因A66G位点基因多态性与血浆Hcy具有显著相关性,随着基因型风险等级的增加,血浆Hcy浓度增高。     

清远地区MTHFR基因多态性与原因不明复发性流产的相关性研究

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点单核苷酸多态性与原因不明复发性流产(URSA)的发生之间的相关性。方法采用前瞻性病例对照研究,选取清远地区71例URSA患者与76例两次正常生育妇女作为对照,采用实时定量PCR分析技术检测MTHFR基因C677T位点单核苷酸多态性情况,并用χ~2检验分析URSA组与对照之间的C677T位点基因型的差异。结果 URSA组MTHFR(C677T)基因纯合突变型TT及等位基因T的频率均高于正常对照组。结论清远地区不明原因复发性流产的发生与MTHFR基因C677T位点纯合突变型TT存在相关性。     

建始地区汉族女性叶酸代谢通路关键酶基因MTHFR、MTRR单核苷酸多态性分布特征调查

目的调查湖北省建始县汉族女性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及甲硫氨酸还原酶(MTRR)A66G位点基因多态性分布情况,分析其遗传风险分布地域性特征,为指导孕龄妇女个性化增补叶酸及出生缺陷一级预防提供依据。方法随机以湖北省恩施州建始县248位汉族女性为研究对象,检测其MTHFR C677T、A1298C及MTRR A66G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,并与我国南北方具有代表性的若干地区进行比较。结果本地区的汉族女性MTHFR 677TT纯合突变基因型频率(14.1%),显著高于我国我们南方城市南宁、琼海和惠州(P0.05),显著低于北方城市乌鲁木齐、尚志、延边、银川、廊坊、烟台、济源、镇江和湘潭(P0.05);等位基因T频率为40.5%,与我国其他地区的比较,结论和C677T位点基因型的情况类似;MTHFR A1298C基因型分布情况与尚志、延边、廊坊、烟台、镇江、湘潭、南宁、惠州和琼海地区的人群差异有统计学意义;MTRR A66G位点的基因型频率和等位基因频率与其它地区比较均无统计学差异(P0.05)。结论建始县的汉族女性MTHFR基因多态性频度分布具有显著的地区特异性,MTRR基因多态性频度分布不具备显著的地区特异性。     

高同型半胱氨酸血症与不明原因反复性自然流产

高HCY血症是不明原因反复性自然流产的独立危险因素,其机制可能与其诱导动脉粥样硬化有关.HCY代谢相关基因多态性如MTHFR C677T、CBS T833C、MS D919G、MTRR A66G突变可能通过影响酶的活性导致高HCY血症,进而与不明原因反复性自然流产发生相关联.补充叶酸、VitB6和VitB12可以治疗和预防高HCY血症,但其远期效果有待进一步研究.     

Association study of four polymorphisms in three folate-related enzyme genes with non-obstructive male infertility

BACKGROUND: Three typical folate metabolism enzymes-i.e. methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MS) and MS reductase (MTRR) in the folate cycle-play a critical role in DNA synthesis and methylation reactions. We evaluated whether polymorphisms of these three enzymes are associated with non-obstructive male infertility. METHOD: Three hundred and sixty patients with non-obstructive infertility and 325 fertile men without any chromosomal abnormalities were included in this study. The single-nucleotide polymorphism (SNP) analysis was performed by pyrosequencing and PCR-restriction fragment length polymorphism (RFLP) analysis RESULTS: The frequencies of MTHFR 677TT and MTRR 66GG genotypes were higher in non-obstructive infertile men compared with those in fertile men. By classifying 360 infertile patients into 174 azoospermia and 186 oligoasthenoteratozoospermia (OAT) subjects, the MTHFR 677TT and MS 2756GG types were significantly associated with the azoospermia group (P = 0.0227 and 0.0063, respectively). The frequency of MTRR 66GG was significant in the OAT group (P = 0.0014 versus fertile males). CONCLUSIONS: By analysis of a large number of subjects and a more specific patient selection, we showed the first genetic evidence that MTHFR C677T, MS A2756G and MTRR A66G genotypes were independently associated with male infertility. Each SNP of the three enzymes may have a different impact on the folate cycle during spermatogenesis.     

MTHFR基因C677T位点多态性与不明原因重复性自然流产的相关性

目的　检测不明原因重复性流产 (unexplained recurrent spontaneous abortion,URSA)患者亚甲基四氢叶酸还原酶 (methylenetetrahydrofolate reductase,MTH FR)基因 C6 77T位点多态性 ,探讨其与血清同型半胱氨酸、叶酸、维生素 B1 2 及与不同临床特征的关系。　方法　 U RSA非孕期患者 5 7例 ,对照组 5 0名 ,空腹血清总高半胱氨酸 (homocysteine,Hcy)的检测采用高压液相色谱法 ,血清叶酸、维生素 B1 2 的检测采用放射免疫法。MTH FR基因 C6 77T多态性采用聚合酶链反应 -限制性片段长度多态性技术检测。结果　 URSA患者组 C/ C基因型频率显著低于正常对照组者 ,总的突变 T等位基因频率显著高于对照组。MTHFR T/ T基因型患者血清 Hcy水平显著增高 ,血清叶酸水平显著降低 ,MTHFR C6 77T基因型在不同年龄、地区、流产时间、流产性质患者的分布差异无显著性。流产 3次以上 (包括 3次 )的患者 6 77T/ T基因型、携带 T等位基因的 C/ T T/ T基因型频率均大于流产次数少于 3次的患者。　结论　 MTH FRC6 77T基因多态性是 URSA发病的遗传风险因素。     

MTRR and MTHFR polymorphism: link to Down syndrome?

Polymorphisms in genes encoding the folate metabolizing enzymes methylenetetrahydrofolate reductase (MTHFR C677T) and methionine synthase reductase (MTRR A66G) have been linked to the etiology of Down syndrome. We examined the prevalence of these variant genotypes in mothers who had given birth to a child with Down syndrome (n = 48) and in control mothers (n = 192), and investigated the biochemical factors influenced by the presence of MTRR A66G and MTHFR C677T. The frequency of the MTRR variant genotypes (AG, GG) was significantly higher in mothers of children with Down syndrome compared to controls (P = 0.0028). MTHFR C677T genotype frequencies were not significantly altered in mothers of children with Down syndrome (P = 0.74). However, mothers who had a MTHFR CT or TT genotype and a MTRR GG genotype had a 2.98-fold increased risk of having a child with Down syndrome (P = 0.02). The MTRR polymorphism did not increase plasma homocysteine. Higher homocysteine was found with the presence of the MTHFR T allele. In conclusion, MTRR A66G is significantly more common in mothers of children with Down syndrome but does not appear to increase the risk for Down syndrome by changing homocysteine metabolism. Women who have both the MTRR and MTHFR variant genotypes are also at increased risk of producing offspring with Down syndrome.     

亚甲基四氢叶酸还原酶基因突变与不明原因复发性流产的关系

目的探讨亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）基因C677T和A1298C突变与不明原因复发性流产（unexplained recurrent miscarriage,u RM）的关系。方法利用聚合酶链式反应（polymerase chain reaction,PCR）和限制性片段长度多态性（restriction fragment length polymorphisms,RFLP）方法,检测52例u RM患者（u RM组）和16例可孕妇女（对照组）MTHFR C677T和MTHFR A1298C位点多态性。结果 u RM组中MTHFR 677C/T（26.9%vs 25.0%,P=1.00）和677T/T（17.3%vs 6.3%,P=0.43）基因型频率以及T等位基因频率（30.8%vs 18.8%,P=0.19）高于对照组但无显著性差异;u RM组中MTHFR 1298 A/C（23.1%vs 18.8%,P=0.98）和1298 C/C（13.5%vs 12.5%,P=0.73）基因型频率以及C等位基因频率（25.0%vs 15.6%,P=0.27）高于对照组亦无显著性差异。结论我们的研究结果表明MTHFR C677T和A1298C基因位点突变可能与u RM无关。     

Polygenic association with total homocysteine in the post-folic acid fortification era: The CARDIA study

Elevated plasma concentration of total homocysteine (tHcy) has been linked with many diseases. tHcy is associated with a variety of factors, including polymorphisms in genes involved in homocysteine metabolism. It is not clear whether US-mandated fortification of grain products with folic acid has affected the association of genetic variants with tHcy levels. We determined tHcy concentrations in sera from 997 Caucasians and 692 African Americans participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study before and after folic acid fortification. DNA was genotyped for variants present in four genes involved in homocysteine metabolism: cystathionine β-synthase (CBS) 844ins68, methionine synthase (MS) 2756A>G; methionine synthase reductase (MTRR) 66A>G and methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C. A greater number of African Americans were homozygous for the MS 2756GG, MTRR 66GG and CBS 844ins68 genotypes compared to Caucasians, while prevalence of MTHFR 677TT and 1298CC genotypes was substantially lower in African Americans compared to Caucasians. The overall variance in tHcy levels at y 0, 7 and 15 that can be explained by the combined presence of all five variants increased slightly over time in Caucasians (17%, y 0; 21%, y 7; and 26%, y 15) and in African Americans (13%, y 0; 17% y 7; and 18% y 15) largely due to decrease in tHcy variance.     

贵州苗族CBS基因与MTHFR基因多态性研究

目的对贵州雷山西江苗族胱硫醚合酶（cystathionine beta-synthase,CBS）基因与亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）基因多态性进行研究。方法采用PCR-限制性片断长度多态性（PCR-RFLP）、PCR-变性梯度凝胶电泳（PCR-DGGE）-基因测序（Gene sequenceing）的方法检测贵州雷山西江苗族CBS基因与MTHFR基因的基因频率及基因型的分布。结果CBS基因的699C→T等位基因频率为5.6%、833 T→C等位基因频率为29.4%。MTHFR基因的677C→T等位基因频率为10.64%、1298 A→C等位基因频率为48.66%。结论同一民族,胱硫醚合酶基因与亚甲基四氢叶酸还原酶基因存在群体差异,这种群体差异可能与人群对多种疾病的群体易感性有关。     

Fetal anticonvulsant syndromes and polymorphisms in MTHFR, MTR, and MTRR

The malformations found in fetal anticonvulsant syndromes (FACS) are associated with folic acid deficiency and methylene-tetrahydrofolate reductase (MTHFR) polymorphisms in the general population. To investigate a possible association between FACS and MTHFR genotype, we recruited 200 mothers who had taken anti-epileptic drugs in pregnancy, and delivered at Aberdeen Maternity Hospital over a 26-year period. Clinical findings in the mothers and their 337 children were documented. A clinical algorithm was devised to diagnose FACS objectively. Case-parent triads were genotyped for polymorphisms in MTHFR, serine hydroxymethyl transferase (SHMT1), methionine synthase (MTR), and methionine synthase reductase (MTRR), and analyzed by log-linear regression. No effect of the child's genotype on congenital malformation, neurodevelopmental disorder or FACS was detected using this method. The risk of having a child with congenital malformation or FACS was three to four times higher for mothers who were MTHFR 677TT homozygotes compared with MTHFR 677CC homozygotes. MTR 2756A > G and MTRR 66A > G genotype frequencies in children with FACS and neurodevelopmental disorder were different from those in healthy blood donor controls.     

Methionine synthase (MTR) 2756 (A --> G) polymorphism,double heterozygosity methionine synthase 2756 AG/methionine synthase reductase (MTRR) 66 AG,and elevated homocysteinemia are three risk factors for having a child with Down syndrome

Contradictory findings have been recently published on the evaluation of genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR 677 C-->T) and methionine synthase reductase (MTRR 66 A-->G) as risk factors for having a child with Down syndrome (DS); however, the influence of polymorphisms of methionine synthase (MTR 2756 A-->G) and of MTHFR 1298 A-->C has never been evaluated. In this study, the risk of being a DS case or having a DS child (case mother) was studied by multiple logistic regression analysis of the independent and combined genotypes and of plasma homocysteine, folates, and vitamin B12 in 92 DS cases and 140 control subjects as well as in 63 case mothers and 72 age-matched control mothers from Sicily. (The MTHFR 677 T allele frequency was not different in DS cases and case mothers, compared to the respective control groups). After adjustment for age, total homocysteine (t-Hcys) and MTR 2756 AG/GG genotype were significant risk factors for having a DS child, with odds ratio (OR) of 6.7 (95% CI: 1.4-32.0, P = 0.016) and of 3.5 (95% CI: 1.2-10.9, P = 0.028), respectively. By comparison, MTR 2756 AG/GG genotype increased significantly the risk of being a DS case, with an OR of 3.8 (95% CI: 1.4-10.5, P = 0.009). The double heterozygosity MTR 2756 AG/MTRR 66 AG was the single combined genotype that was a significant risk factor for having a DS child, with an OR estimated at 5.0 (95% CI: 1.1-24.1), after adjustment for t-Hcys. In conclusion, our results provide evidences that homocysteine and MTR genetic polymorphism are two potent risk factors for mothers to have a DS child in Sicily.