Single nucleotide polymorphism C677T in the methylenetetrahydrofolate reductase gene might be a genetic risk factor for infertility for Chinese men with azoospermia or severe oligozoospermia

Aim： To analyze the distribution of the single nucleotide polymorphism （SNP） C677T in the methylenetetrahydrofolate reductase （MTHFR） gene in 355 infertile Chinese patients with idiopathic azoospermia or severe oligozoospermia and 252 fertile Chinese men as controls to explore the possible association of the SNP and male infertility. Methods： Using the polymerase chain reaction （PCR）-restriction fragment length polymorphism technique, the allele and genotype distribution of SNP C677T in the MTHFR gene were investigated in both patients and controls. Results： The frequencies of allele T （40.9% vs 30.4%, P = 0.002, odds ration [OR] = 1.58, 95% confidence interval [CI]： 1.24-2.02） and mutant homozygote （TT） （18.3% vs. 11.5%, P = 0.023, OR = 1.72, 95% CI： 1.07-2.76） as well as carrier with allele （TT ＋ CT） （63.4% vs. 49.2%, P = 0.0005, OR = 1.79, 95% CI： 1.29-2.48） in infertile patients were significantly higher than those in controls. After patient stratification, the significant differences in distribution of the SNP between each patient subgroup and control group still remained. Conclusion： Our findings indicate that there is an association of SNP C677T in the MTHFR gene with male infertility, suggesting that this polymorphism might be a genetic risk factor for male infertility in Chinese men.

Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and gastric cancer susceptibility

AIM: To identify the association between methylenetetrahydrofolate reductase(MTHFR) polymorphisms and gastric cancer(GC) susceptibility.METHODS: Systematic searches were performed on the electronic databases PubMed, ISI, Web of knowledge, CNKI and Wanfang, as well as manual searching of the references of the identified articles. A total of 26 papers were included in this meta-analysis. Overall and subgroup analyses were performed. Odds ratio(OR) and 95%CI were used to evaluate the associations between MTHFR polymorphisms and GC risk. The I2 statistics were used to evaluate between-study heterogeneity. Sensitivity analysis was also performed.RESULTS: Increased risk was found for the MTHFRC677T polymorphism under four genetic models(TT + CT vs CC: OR = 1.23, P = 0.002; T vs C: OR = 1.15, P = 0.001; TT vs CC: OR = 1.37, P = 0.0005; TT vs CT + CC: OR = 1.17, P = 0.0008). Subgroup analysis by ethnicity suggested that C677 T polymorphism conferred a risk of GC in eastern but not in western populations. Stratification by tumor site showed an association between the C677 T polymorphism and gastric cardia cancer and non-cardia GC in the worldwide population and in eastern populations. Regardless of comparisons with controls or diffuse-type GC, a positive association was found for the C677 T polymorphism and an increased risk of intestinal-type GC in the whole population and in western populations. With regard to the A1298 C polymorphism, we found that genotype CC was significantly decreased and conferred protection against GC in eastern populations(CC vs AA: OR = 0.44, P = 0.03; CC vs AC + AA: OR = 0.46, P = 0.04). CONCLUSION: MTHFR C677 T polymorphism is a risk factor for GC, and the A1298 C polymorphism may be a protective factor against GC in eastern populations.

Association Between Homocysteine Level and Methylenetetrahydrofolate Reductase Gene Polymorphisms in Type 2 Diabetes Accompanied by Dyslipidemia

Objective To investigate the association between total homocysteine(tHcy)level in plasma and methylenetetrahydrofblate reductase(MTHFR)C677T and A1298C genetic polymorphisms in a Chinese Han nationality population with type 2 diabetes mellitus(T2DM)accompanied by dyslipidemia.Methods This case-control study enrolled T2DM patients with dyslipidemia and without dyslipidemia respectively.Sanger dideoxy-mediated chain-termination method was used to detect the gene polymorphisms of MTHFR C677T and A1298C.Plasma tHcy and lipid levels were measured as well.The genotype frequency and allele frequency between the dyslipidemia and non-dyslipidemia groups were compared by using Chi-square test.Plasma tHcy level ofT2DM patients who carried the different genotypes was compared by Student's t test.Results Finally,82 T2DM patients with dyslipidemia and 94 ones without dyslipidemia were included in this study.There was a significant correlation between tHcy level and MTHFR C677T gene polymorphism inT2DM patients(t=2.27,P=0.02).Moreover,the plasma tHcy level in the dyslipidemia patients who carried MTHFR 677TT genotype was significantly higher than that in those with CT+CC genotype(13.62+6.97 vs.10.95+3.62pmol/L,t=2.2O,P=0.03);while for patients without dyslipidemia,comparison of the tHcy level between those who carried the above two alleles showed no significantly difference(13.34±6.03 vs.12.04±5.09μmol/L,t=1.08,P=0.29).Conclusion MTHFR 677TT genotype might associate with higher tHcy level in T2DM patients with dyslipidemia.

Methylenetetrahydrofolate Reductase Gene Polymorphism C677T is Associated with Increased Risk of Coronary Heart Disease in Chinese Type 2 Diabetic Patients

Objective Chronic cardiovascular diseases induced by long-term poor blood glucose control are the main cause of death in patients with type 2 diabetes mellitus(T2DM).Previous researches report that methylenetetrahydrofolate reductase gene(MTHFR)polymorphisms might influence the occurrence of coronary heart disease(CHD)in T2DM patients.The purpose of this study was to evaluate whether MTHFR C677T and A1298C mutations are associated with the risk of CHD inT2DM patients.Methods A total of 197 subjects with T2DM were studied,of which 95 patients with CHD.The genotypes of MTHFR C677T and A1298C were analyzed by using dideoxy chain-termination method,and compared between patients with CHD and those without CHD.Results We found that the frequency of the 677T allele was significantly higher in T2DM patients with CHD than those without CHD(P=0.011).However,there was no significant difference in any of the examined haplotypes between T2DM patients with and without CHD.Furthermore,the 677T allele was associated with a higher risk of CHD development in diabetic patients with lower homocysteine(Hey)levels(≤15μmol/L)(P=0.006),while no effect of MTHFR gene polymorphism on the incidence of CHD was found in patients with higher Hey levels(>15 μmol/L)(P=0.491).Conclusion The MTHFR C677T gene polymorphism is associated with the risk of CHD of diabetic patients and could be used as an effective marker for CHD in Chinese diabetic populations with normal Hey levels.

ASSOCIATION OF PLASMA HOMOCYSTEINE LEVEL AND N^5, N^(10) -METHYLENETETRAHYDROFOLATE REDUCTASE GENE POLYMORPHISM WITH CEREBRAL INFARCTION

Objective. To investigate the relationship of plasma homocysteine (Hcy) level to stroke and genetic factor to elevated plasma Hcy level.Methods. The plasma Hcy level was measured by capillary electrophoresis- ultraviolet detection and the gene polymorphism of N5, N10 - methylenetetrahydrofolate reductase (MTHFR) was studied with PCR - RFLP assay in 43 patients with cortical cerebral infarction and 42 healthy controls.Results. The plasma Hcy level of the patients ( 19. 3 + 6. 0 μ mol/L) was markedly higher than that of the controls (13.7 + 5.4 μ mol/L) ( t = 4. 16, P ＜ 0. 001). There are 3 genotypes, C/C, C/T and T/T, about base - variation of MTHFR gene at locus 677. The plasma Hcy level of the subjects with T/T genotype was higher than that of subjects with other genotypes. However, the frequencies of each genotype and allele were not significantly different between the patients and the controls.Conclusions. The elevated plasma Hcy level is a risk factor for atherothrombotic cerebral infarction, and is related to the C→T mutation at locus 677 of MTHFR gene.

Is the C677T polymorphism in methylenetetrahydrofolate reductase gene or plasma homocysteine a risk factor for diabetic peripheral neuropathy in Chinese individuals?

The present study enrolled 251 diabetic patients, including 101 with neuropathy and 150 without neuropathy. Of the 150 patients, 100 had no complications, such as retinopathy, nephropathy, or neuropathy. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to identify methylenetetrahydrofolate reductase gene variants. Plasma homocysteine levels were also measured. Homocysteine levels and the frequency of hyperhomocysteinemia were significantly higher in patients with diabetic peripheral neuropathy compared with diabetic patients without neuropathy （P 〈 0.05）. In logistic regression analysis with neuropathy as the dependent variable, the frequency of C677T in methylenetetrahydrofolate reductase was significantly higher in patients with diabetic peripheral neuropathy compared with patients without diabetic complications. Homocysteine levels were significantly higher in patients with diabetic peripheral neuropathy carrying the 677T allele and low folic acid levels. In conclusion, hyperhomocysteinemia is an independent risk factor for diabetic neuropathy in Chinese patients with diabetes. The C677T polymorphism in methylenetetrahydrofolate reductase and low folic acid levels may be risk factors for diabetic peripheral neuropathy in Chinese patients with diabetes.

Folate levels in mucosal tissue but not methylenetetrahydrofolate reductase polymorphisms are associated with gastric carcinogenesis

AIM: To evaluate whether folate levels in mucosal tissue and some common methylenetetrahydrofolate reductase (MTHFR) variants are associated with the risk of gastric cancer through DNA methylation. METHODS: Real-time PCR was used to study the expression of tumor related genes in 76 mucosal tissue samples from 38 patients with gastric cancer. Samples from the gastroscopic biopsy tissues of 34 patients with chronic superficial gastritis (CSG) were used as controls. Folate concentrations in these tissues were detected by the FOL ACS: 180 automated chemiluminescence system. MTHFR polymorphisms were analyzed by PCR-RFLP, and the promoter methylation of tumor-related genes was determined by methylation-specific PCR (MSP). RESULTS: Folate concentrations were significantly higher in CSG than in cancerous tissues. Decreased expression and methylation of c-myc accompanied higher folate concentrations. Promoter hypermethylation and loss of p16INK4A in samples with MTHFR 677CC were more frequent than in samples with the 677TT or 677CT genotype. And the promoter hypermethylation and loss of p21WAF1 in samples with MTHFR 677CT were more frequent than when 677CC or 677TT was present. The 677CT genotype showed a non-significant higher risk for gastric cancer as compared with the 677CC genotype. CONCLUSION: Lower folate levels in gastric mucosal tissue may confer a higher risk of gastric carcinogenesisthrough hypomethylation and overexpression of c-myc.

Association of methylenetetrahydrofolate reductase C677T polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

Objectives The association of methylenetetrahy-drofolate reductase(MTHFR) gene polymorphism and serum lipid profiles is still controversial in diverse ethnics.Bai Ku Yao is an isolated subgroup of the Yao minority in China. The aim of the present study was to eveluate the association of MTHFR C677Tpolymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations.Methods A total of 780 subjects of Bai Ku Yao and 686 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples.Genotyping of the MTHFR C677T was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis,and then confirmed by direct sequencing.Results The levels of serum total cholesterol(TC),high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol(LDL-C), apolipoprotein(Apo) AI and ApoB were lower in Bai Ku Yao than in Han(P【0.05-0.001).The frequency of C and T alleles was 77.4%and 22.6%in Bai Ku Yao,and 60.9%and 39.1%in Han(P【0.001);respectively.The frequency of CC,CT and TT genotypes was 58.7%,37.3%and 4.0%in Bai Ku Yao,and 32.6%,56.4%and 11.0%in Han(P【 0.001);respectively.The levels of TC and LDL-C in both ethnic groups were significant differences among the three genotypes(P【0.05-0.01).The T allele carriers had higher serum TC and LDL-C levels than the T allele noncarriers. The levels of ApoB in Han were significant differences among the three genotypes(P【0.05).The T allele carriers had higher serum ApoB levels as compared with the T allele noncarriers. The levels of TC,TG and LDL-C in Bai Ku Yao were correlated with genotypes(P【0.05-0.001),whereas the levels of LDL-C in Han were associated with genotypes(P【 0.001).Serum lipid parameters were also correlated with sex, age,body massindex,alcohol consumption,cigarette smoking, and blood pressure in the both ethnic groups.Conclusions The differences in serum TC,TG,LDL-C and ApoB levels between the two ethnic groups might partly result from different genotypic and allelic frequencies of the MTHFR C677Tor differentMTHFR gene-enviromental interactions.

Polymorphisms in methylenetetrahydrofolate reductase gene: Their impact on liver steatosis and fibrosis of chronic hepatitis c patients

Aim & Background: The mechanism of steatosis in Hepatitis C virus infection is multifactorial;therefore, it is complex and unclear. The aim of this study was to investigate the effects of methylentetrahydrofolate reductase (MTHFR) gene polymorphisms on the course of chronic hepatitis C virus infection and the development of steatosis due to hepatitis C virus. Methods: This study included 109 patients with chronic hepatitis C virus infection. Necroinflammatory activity, degrees of fibrosis and steatosis and MTHFR gene polymorphisms were investigated. Polymerase chain reaction-restriction fragment length polymorphism was used to determine MTHFR C677T and A1298C polymorphisms. Results: Fibrosis was correlated with age (r = 0.336, p = 0.002), platelet (r = ?0.448, p < 0.0001), ALT (r = 0.241, p = 0.026), AST (r = 0.361) and GGT (r = 0.224, p = 0.039). Steatosis was only correlated with fibrosis. MTHFR C677T and A1298C polymorphisms did not have a significant effect on the degree of steatosis (p = 0.857, p = 0.202 respectively). There was a relation between MTHFR C677T and the degree of fibrosis but not A1298C (p = 0.014, p = 0.187 respectively). Conclusion: We found that MTHFR C677T polymorphism contributed to the development of fibrosis in patients with chronic hepatitis C virus infection.

A review of methylenetetrahydrofolate reductase in one-carbon metabolism and psychiatric disorders

Methylenetetrahydrofolate reductase(MTHFR)is a key enzyme for the critical process of one-carbon circulation,which convert5,10-methylenetetrahydrofolate to5-methyltetrahydrofolate and participate in folate and homocysteine conversion correlated to methyl group supply.The enzyme activity decline depends on the gene polymorphism.MTHFR impacts on the methylation process which is related to psychiatric diseases.Studies have shown association between MTHFR gene polymorphisms and mental disorders,some of which stratified by folate and cobalamin levels.In this review,we will summarize the testimony on the relationship between methylation and MTHFR polymorphism as well as the implication on psychiatric diseases by MTHFR mutation.

Correlation between methylenetetrahydrofolate reductase gene C677T polymorphism and preeclampsia in pregnant women

Objective: To study the correlation between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and preeclampsia in pregnant women. Methods: Pregnant women who were diagnosed with preeclampsia in Jianshi People's Hospital between July 2014 and March 2017 were selected as the PE group of the research, and healthy pregnant women who received antenatal care and gave birth in Jianshi People's Hospital during the same period were selected as the control group of the research. The MTHFR gene C677T polymorphism in peripheral blood, the contents of homocysteine (Hcy) metabolism indexes and the expression of apoptosis genes and invasion genes were determined. Results: The proportion of MTHFR gene C677T locus TT genotype in peripheral blood of PE group was significantly higher than that of control group while the proportion of CT and CC genotypes were significantly lower than those of control group;Hcy levels in serum and placenta as well as FasL, Caspase-8, Bax, Caspase-9 and Caspase-3 mRNA expression in placenta of PE women with TT genotype were significantly higher than those of PE women with CT genotype and CC genotype while folic acid levels in serum and placenta as well as Notch-1, N-cadherin, Vimentin, CatL and CatB mRNA expression in placenta were significantly lower than those of PE women with CT genotype and CC genotype. Conclusion: MTHFR gene C677T locus mutation can participate in the occurrence of preeclampsia by affecting the Hcy metabolism as well as the expression of apoptosis genes and invasion genes.

Correlation of methylenetetrahydrofolate reductase polymorphism with Hcy metabolism and inflammatory response in patients with recurrent cerebral infarction

Objective:To study the correlation of methylenetetrahydrofolate reductase (MTHFR) polymorphism with Hcy metabolism and inflammatory response in patients with recurrent cerebral infarction.Methods: 40 patients with recurrent cerebral infarction who were treated in Yulin Third Hospital between December 2013 and December 2016 were selected as recurrent group, 58 patients with primary cerebral infarction were selected as primary group, and 60 healthy volunteers were selected as control group. Peripheral blood MTHFR gene C677T polymorphism and serum levels of Hcy metabolism indexes and inflammatory response indicators were determined.Results: CC genotype constituent ratio of recurrent group was significantly lower than that of primary group and control group while CT genotype and TT genotype constituent ratio were significantly higher than those of primary group and control group;serum Hcy, HMGB1, sCD40L, YKL-40, Lp-PLA2 and MMP-9 levels in recurrent group and primary group were significantly higher than those in control group while VitB12 and FA levels were significantly lower than those in control group;serum Hcy, HMGB1, sCD40L, YKL-40, Lp-PLA2 and MMP-9 levels in recurrent group were significantly higher than those in primary group while VitB12 and FA levels were significantly lower than those in primary group. Serum Hcy, HMGB1, sCD40L, YKL-40, Lp-PLA2 and MMP-9 levels in patients with CC genotype were significantly lower than those in patients with CT genotype and TT genotype while VitB12 and FA levels were significantly higher than those in patients with CT genotype and TT genotype;serum Hcy, HMGB1, sCD40L, YKL-40, Lp-PLA2 and MMP-9 levels in patients with CT genotype were significantly lower than those in patients with TT genotype while VitB12 and FA levels were significantly higher than those in patients with TT genotype.Conclusion: MTHFR gene C677T polymorphism is closely related to the recurrence of cerebral infarction, and allele C mutation to T will affect Hcy metabolism and aggravate inflammatory response.

普通叶酸与活性叶酸补充对于MTHFR 677TT型不明原因反复流产患者红细胞叶酸水平的影响

目的·研究普通叶酸与活性叶酸补充对亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)677TT型不明原因反复流产(unexplained recurrent pregnancy loss,URPL)患者红细胞叶酸水平的影响。方法·选取2021年1—12月于北京大学第三医院生殖医学中心就诊的MTHFR 677TT型URPL患者45例。按照叶酸补充方式将其分为3组,包括A组16例(研究开始前尚未接受任何形式的叶酸补充,研究开始后进行活性叶酸补充),B组15例(研究开始前进行过普通叶酸的补充,研究开始后进行活性叶酸补充),以及C组14例(研究开始前进行过普通叶酸的补充,研究开始后进行普通叶酸与活性叶酸联合补充)。分别于入组时(第一次)、入组补充后(第二次)对3组患者的红细胞5-甲基四氢叶酸(5-methyltetrahydrofolate,5-MTHF)浓度进行检测,并开展比较。结果·在3组患者中,任意2组的第一次红细胞5-MTHF浓度间差异均无统计学意义。与第一次红细胞5-MTHF浓度相比,3组患者的第二次红细胞5-MTHF浓度均有提高(均P=0.000),且B组患者的红细胞5-MTHF浓度的增幅高于A组(t=2.373,P=0.049),但与C组间差异无统计学意义。结论·与补充普通叶酸相比,补充活性叶酸可以更好地在短时间内提高MTHFR 677TT型URPL患者的红细胞叶酸水平。

MTHFR C677T基因多态性方法学比较

目的评价比较实时荧光定量PCR法与PCR-金磁微粒层析法两种方法检测5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性的一致性、检测限、特异性。方法随机选取首都医科大学附属北京天坛医院采集的50例静脉抗凝全血,均通过磁珠法提取基因组DNA,依照最新版分子诊断检验程序性能验证指南(CNAS-GL039)要求对两种方法学的一致性、检测限、特异性进行性能评价。结果实时荧光定量PCR与PCR-金磁微粒层析具有高度的一致性,采用两种方法检测50例样本的一致性为100%;两种方法检测交叉反应中检测结果未受影响,基因型之间无交叉污染情况;检测限验证中前者的灵敏度更高,最低检测限可达0.078125ng/μL,后者的最低检测限为0.625ng/μL。结论实时荧光定量PCR法与PCR-金磁微粒层析法均具有操作简便、灵敏度高,特异性强的特点,可用于人类MTHFR基因多态性检测,同时能够对叶酸代谢作出有效的诊断,需根据临床实验室的需求,选择合理有效的检测方法。

830例育龄妇女MTHFR基因A1298C位点多态性研究

目的探讨育龄妇女5,10-亚甲基四氢叶酸还原酶(MTHFR)基因A1298C位点基因多态性与年龄及民族是否有关,为指导育龄期妇女进行叶酸补充提供参考。方法采集2019年1月至2023年4月在该院门诊进行孕前或孕期行优生健康检查的汉族及其他民族的育龄女性外周血标本830例。采用PCR荧光探针法检测MTHFR基因A1298C位点的多态性,进行各年龄段及不同民族人群间基因多态性位点基因型分布比较。结果830例育龄期妇女中,MTHFR基因A1298C位点AA、AC及CC基因型频率分别为69.64%、27.35%和3.01%;各年龄段育龄女性MTHFR基因A1298C位点的基因型和等位基因频数和频率分布情况进行比较,差异均无统计学意义(P>0.05);汉族与藏族、回族、土族及蒙古族育龄女性间的MTHFR基因A1298C位点的基因型和等位基因频数和频率分布情况比较,差异均无统计学意义(P>0.05)。结论育龄妇女MTHFR基因A1298C位点多态性与年龄及民族无关,但有不同于其他地区的MTHFR基因A1298C位点多态性分布特征。

MTHFR基因多态性对骨肉瘤患者首次应用大剂量甲氨蝶呤后不良反应的影响

目的探讨MTHFR基因多态性对骨肉瘤患者首次应用大剂量甲氨蝶呤(HD-MTX)后不良反应的影响。方法采用前瞻性研究方法。选择东部战区总医院53例首次入院进行HD-MTX治疗的骨肉瘤患者,根据其人口学因素及MTHFR基因中rs1801133位点的基因多态性确定HD-MTX给药剂量并进行全程化药学监护,收集第1个化疗周期后该药的肝、肾、血液毒性和胃肠道反应数据。采用单因素分析和二元Logistic回归分析对MTX给药剂量、24 h血药浓度、rs1801133位点基因型与上述4种不良反应之间的相关性进行分析。结果CC野生型患者的MTX给药剂量显著高于TT突变型患者(7.97 g/m2 vs.6.98 g/m2,P=0.030),但这种差异不影响MTX的0 h和24 h血药浓度。上述4种不良反应与MTX的给药剂量无相关性。二元Logistic回归分析结果显示,每携带一个T等位基因,患者发生血液学毒性的风险会升高4.13倍(95%置信区间为1.35~12.62,P=0.013)。当MTX 24 h血药浓度阈值设定为2.65μmol/L时,肝功能损害预测的灵敏度为53.33%,特异性为86.96%;当该阈值设定为7.28μmol/L时,肾功能损害预测的灵敏度为100%,特异性为81.63%。结论MTHFR基因中rs1801133位点的基因多态性与MTX的血液学毒性相关;首次应用HD-MTX并且携带T等位基因的患者,其血液学毒性风险较高。MTX 24 h血药浓度与该药的肝、肾毒性相关,监测患者的MTX 24 h血药浓度可以预测肝、肾毒性并及早采取干预措施。

新疆昌吉地区育龄女性MTHFR基因C677T位点多态性分布及其与不良妊娠结局关系

目的:分析新疆昌吉地区育龄女性5,10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点基因多态性分布及其与不良妊娠结局可能关系。方法:采集2023年5月-2024年2月本院就诊的育龄女性642例;另选有妊娠史285例,其中不良妊娠史146例为不良妊娠史组,正常生育无不良妊娠史139例为正常组。采集上述女性静脉血,采用荧光定量聚合酶链反应方法检测MTHFR基因C677T位点的多态性,分析其多态性特点。结果:642例育龄女性中MTHFR基因C677T位点CC、CT及TT基因型频率分别为26.0%、51.3%、22.7%,与中国南方和北方城市比较有差异(P<0.05),本次研究不同年龄段基因类型以及等位基因出现频数、频率比较未见差异(P>0.05)。不良妊娠史组及正常组正常无风险基因型(CC型)构成比分别为22.6%和27.3%,中度风险(CT型)的构成比分别为50.7%和51.8%,高度风险(TT型)的构成比分别为26.7%和20.9%,两组不同类型基因型比较有差异(P<0.05)。结论:MTHFR基因C677T位点基因型分布存在地区差异,纯合突变(TT型)与不良妊娠结局可能有关。

亚甲基四氢叶酸还原酶缺乏症致脑积水患儿2例临床及MTHFR基因变异分析

目的 探讨以婴儿期脑积水为突出表现的亚甲基四氢叶酸还原酶缺乏症患儿的临床特点、治疗及预后。方法 2例患儿因脑积水于北京大学第一医院儿科就诊,经血清总同型半胱氨酸、血液氨基酸及酰基肉碱谱、尿有机酸和基因分析确诊,对患儿的临床特点、代谢异常、MTHFR基因变异、诊断、治疗及预后等进行回顾性研究。结果 2例患儿为男童,分别于2月龄及4月龄起病,以脑积水及癫痫发作为主要表现,血清总同型半胱氨酸显著增高,血甲硫氨酸降低或处于正常低值,尿有机酸正常,头颅影像检查发现严重脑积水。两患儿服用甜菜碱、亚叶酸钙、钴胺素等治疗后血清总同型半胱氨酸下降,侧脑室腹腔分流手术后颅压改善,但智力运动发育明显迟缓,仍有癫痫发作。两患儿MTHFR基因均存在复合杂合变异,确诊为亚甲基四氢叶酸还原酶缺乏症所致同型半胱氨酸血症2型。4种变异中1种为已知致病变异,3种为未报道的新变异。结论 亚甲基四氢叶酸还原酶缺乏症患儿可于婴儿早期发生脑积水及癫痫等严重神经系统疾病,血清总同型半胱氨酸及基因检测是早期诊断的关键。

我院生殖助孕门诊患者叶酸代谢酶MTHFR 基因多态性的调查分析

目的:调查分析本院生殖助孕门诊患者MTHFR基因多态性分布及特征。方法:采用回顾性研究方法,调取2018年8月17日—2022年4月30日于本院生殖助孕妇科和生殖助孕男科门诊就医的6820例患者作为研究对象,使用PCR-芯片杂交法检测MTHFR C677T的基因型,统计基因型和等位基因频率。结果:女性患者MTHFR C677T野生型(CC)、杂合突变型(CT)和纯合突变型(TT)的频率分别为19.13%、48.77%和32.10%,C、T等位基因频率分别为43.51%和56.49%。男性患者MTHFR C677T基因CC、CT和TT的频率分别为18.89%、48.14%和32.97%,C、T等位基因频率分别为42.96%和57.04%。男性和女性患者MTHFR C677T基因型与等位基因频率差异无统计学意义(P>0.05)。不同年龄段患者的上述位点基因型分布比较,差异无统计学意义(P>0.05)。结论:本院生殖助科门诊患者MTHFR C677T基因多态性频率在不同年龄段及男性和女性患者中的分布无差异。