母亲叶酸代谢相关基因多态性与唐氏综合征发生的关系

目的研究叶酸代谢相关基因多态性在浙南地区汉族妇女中的分布,探讨其与唐氏综合征(Down’s Syn-drome,DS)发生的关系。方法对84例已生育DS患儿的母亲(观察组)和120例生育过正常儿童的母亲(对照组)采用PCR扩增及DNA测序法检测亚甲基四氢叶酸还原酶(MTHFR)基因C677T、A1298C位点;甲硫氨酸合成酶(MTR)基因A2756G位点单核苷酸多态性。结果 MTHFR 677 T基因及CT、TT基因型、MTHFR 1298 C基因及AC、CC基因型、MTR 2756 G基因及AG基因型频率观察组与对照组比较均无统计学意义(P>0.05)。三个位点基因型频率联合分析两组也不存在统计学意义(OR=0.692,P>0.05)。结论浙南地区汉族妇女MTHFR C677T、FTHFR A1298C、MTR A2756G基因型不是DS发生的风险因素;三个基因型的联合频率也未见增加DS发生的风险。     

叶酸代谢相关基因多态性及血浆同型半胱氨酸与唐氏综合征关系研究

目的研究叶酸代谢相关的亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTH-FR)基因多态性与唐氏综合征(Down syndrome,DS)发生的关系。方法选择100例生育过DS患儿的汉族母亲及100名相匹配的正常对照组母亲,PCR-限制性片段长度多态性方法检测MTHFR677C/T的基因型,化学发光法检测血浆中同型半胱氨酸(homocysteine,HCY)的水平。结果病例组MTHFR677T等位基因的频率较对照组增高,差异有统计学意义(P=0.002);杂合基因型CT的比值比为2.12(95%CI:1.14～3.94);而纯合基因型TT的比值比为3.43(95%CI:1.41～8.36)。平均血浆HCY浓度在病例组[(9.04±3.85)μmol/L]较对照组[(6.53±2.06)μmol/L]增高,差异有统计学意义(P<0.01)。MTHFR677位点一个和(或)两个等位基因C→T的变异,不论在病例组还是对照组均可引起HCY水平的显著增加(P<0.01)。同为MTHFR677CC基因型,病例组中的血浆HCY浓度仍较对照组增高(P<0.01),这种增加不依赖于MTHFR的基因型。结论血浆HCY和叶酸代谢相关基因的遗传多态性是汉族妇女生育DS患儿的危险因素。     

唐氏综合征患儿母亲MTHFR C677T基因多态性及血浆叶酸、同型半胱氨酸水平的研究

目的研究浙南地区汉族妇女叶酸及代谢产物同型半胱氨酸水平、亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点多态性与唐氏综合征(Down’s Syndrome,DS)发生的关系。方法对84例已生育DS患儿的母亲(观察组)和120例生育过正常儿童的母亲(对照组)采用PCR扩增及DNA测序法检测亚甲基四氢叶酸还原酶基因MTHFR C677T单核苷酸多态性;免疫发光法检测叶酸(Folate)及循环酶法检测血浆同型半胱氨酸(Hcy)水平。结果 MTHFR 677 T基因及CT、TT基因型的频率两组无统计学意义(P>0.05)。对观察组与对照组的部分标本行血浆Folate与Hcy水平测定,观察组Folate水平显著高于对照组(t=-5.572,P<0.05);Hcy水平两组平均水平无统计学意义(t=0.152,P>0.05);Fo-late与Hcy水平呈负相关关系(r=-0.217,P<0.05)。观察组与对照组MTHFR 677CT、TT基因型与CC基因型Hcy水平比较均无统计学意义(P>0.05),观察组TT基因型Hcy水平比对照组有显著性升高(t=2.546,P<0.05)。结论本研究MTHFR C677T位点不是浙南地区汉族妇女DS的风险因素;DS母亲Folate水平高于对照组及MTHFR 677 TT基因型Hcy水平高于对照组,可能存在影响叶酸代谢的其他相关基因的多态性或营养的缺乏,有待进一步深入研究。     

MTHFR基因C677T多态性与孤独症患儿问题行为及遗传模式的相关性CSCD

目的探讨亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因C677T多态性与孤独症的相关性。方法选择93例孤独症患儿作为观察组,93例健康儿童作为对照组。检测其MTHFR基因C677T位点的基因型,并分析其与患儿问题行为及遗传模式的相关性。结果MTHFR基因C677T位点具有CC、CT、TT 3种基因型。观察组CC基因型较对照组少,TT基因型较对照组多(P<0.05)。三种多态性中,目光接触、复杂肢体动作、自残行为和过度活跃4种问题行为出现频率存在统计学差异(P<0.05)。回归分析显示存在统计学差异的4种问题行为1与2编码程度的至少有一个T等位基因。MTHFR基因C677T基因型在隐性遗传模型及等位基因遗传模型下与孤独症存在关联(P<0.05)。结论MTHFR基因C677T多态性与孤独症患儿问题行为及遗传相关,基因型为TT或携带T等位基因的患儿发生孤独症的风险高并与目光接触、复杂肢体动作、自残行为和过度活跃1与2编码程度相关。     

MTHFR基因多态性与非综合征性唇腭裂的相关性研究

目的:探讨5,10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性与非综合征性唇腭裂(NSCLP)遗传易感性的相关性。方法:选取2014年6月至2015年5月在我院治疗的NSCLP患者100例(病例组A),其中单纯性腭裂(CPO组)23例,唇裂伴或不伴腭裂(CL/P组)77例;同时选取100名正常儿童(对照组A)、100名生育过NSCLP患儿母亲(病例组B)和100名正常出生儿母亲(对照组B),采用聚合酶联式反应-限制性片段长度多态性基因分型技术检测各组MTHFR基因C677T突变。结果:病例组A中,CL/P组C、T等位基因频率为55.84%和44.16%,CPO组分别为54.35%和45.65%,对照组A分别为75.00%和25.00%,CL/P组和CPO组T等位基因频率明显高于对照组A,差异有统计学意义(P0.05);CT基因型个体患CL/P的风险是CC基因型个体的2.39倍,患CPO的风险是CC基因型个体的2.98倍;TT基因型个体患CL/P的风险是CC基因型个体的6.70倍,患CPO的风险是CC基因型个体的7.33倍;病例组B和对照组B的等位基因频率和基因型构成情况比较差异无统计学意义(P0.05)。结论:MTHFR基因C677T突变可能是NSCLP发生的遗传危险因素之一,但母亲MTHFR基因C677T突变可能与子代发生NSCLP无关。     

亚甲基四氢叶酸还原酶基因多态性与青海汉族妊娠期高血压疾病的相关性

目的 探讨亚甲基四氢叶酸还原酶（MTHFR）基因-677C/T（rs1801133）多态性与青海汉族妇女妊娠期高血压疾病（HDP）的相关性。 方法 选择青海省HDP患者 139 例（HDP组）,正常妊娠孕妇 145 例（对照组）,应用限制性内切酶片段长度多态性聚合酶链反应（PCR-RFLP）方法,检测HDP组和对照组MTHFR-677C/T多态性分型并测序验证。 结果 HDP组和对照组MTHFR基因CC、CT、TT基因型频率分别为54.68%、35.25%、10.07% 和69.66%、22.06%、8.28%,CC基因型频率HDP组54.68%低于对照组69.66%（P<0.05）,CT基因型频率HDP组35.25%高于对照组22.06%（P<0.05）,而TT基因型频率HDP组和对照组之间差异无统计学意义（P>0.05）;HDP组和对照组MTHFR-677C/T多态性C和T等位基因频率分布有差异（P<0.05）,HDP组T等位基因频率高于对照组（χ²=5.568,P<0.05）。 结论 MTHFR基因-677C/T多态性与青海汉族HDP相关,MTHFR基因-677C/T多态性中T等位基因可能是HDP的易感基因,CT基因型为HDP的易感基因型。     

山东地区非综合征性唇腭裂患者MTHFR基因C677T的多态性研究

目的探讨山东地区亚甲基四氢叶酸还原酶(MTHFR)基因C677T的多态性与非综合征性唇腭裂(NSCL/P)的关系。方法运用聚合酶链反应-限制性内切酶片段长度多态性分析技术(PCR-RFLP),对2006年8月至2008年8月曾在齐鲁医院治疗的来自山东地区NSCL/P患儿35例和健康查体的正常儿童51例MTHFR基因的C677T基因型检测分析。结果患者组与对照组的基因型构成比有统计学意义(χ2=8.770,P=0.0121)。对T分析,计算得到携带T等位基因的儿童患非综合征性唇腭裂的危险性是不携带T等位基因儿童的2.568倍(OR=2.568,95%CI:1.324-4.979)。TT突变纯合子患非综合征性唇腭裂的危险性是非TT纯合子的3.095倍(OR=6.088,95%CI:1.240-7.722)。结论 MTHFRC677T的T等位基因可能是山东地区非综合征性唇腭裂的遗传风险因子。     

贵州荔波汉族与雷山苗族MTHFR基因多态性分布的比较

目的比较贵州汉族、苗族亚甲基四氢叶酸还原酶基因(MTHFR)多态性的分布情况,获取 MTHFR C677T和A1298C位点的群体遗传学数据.方法应用PCR-RLFP技术调查了贵州荔波汉族及雷山苗族MTHFR基因型的分布.结果汉族MTHFR 677位T等位基因频率为22.7%低于中国北方汉族,与苗族(10.64%)差异有显著性.苗族1298位C等位基因频率为48.66%高于有文献报道的种族和民族,与汉族(28.85%)差异有显著性.677TT/1298CC双杂合子的分布频率分别是16.66%,11.11%.在苗族还发现一例677TT/1298CC双纯合子.结论 MTHFR两个位点多态性在贵州汉族和苗族有民族差异;苗族A1298C位点C等位基因频率是有文献报道最高的民族.     

MTHFR C677T多态性与脓毒血症的关系

目的 探讨MTHFR C677T基因多态性（SNP）与脓毒血症的关系。方法 选择2014年1月~2018年6月我院住院的脓毒血症患者98例,采用梯度PCR及DNA测序技术,检测MTHFR C677T基因型,比较不同T淋巴细胞凋亡比例脓毒血症患者MTHFR C677T基因型分布情况及MTHFR C677T多态性与脓毒血症的关系。结果 MTHFR C677各位点基因型在T淋巴细胞中的凋亡比例方面比较,差异均无统计学意义（P＞0.05）;APACHEⅡ＜4分,SOFA＜2分的CT比例高于CC与TT基因型,降钙素原减少比例TT低于CC基因型与CT基因型,差异均有统计学意义（P＜0.05）,28 天死亡人数比例TT低于CC基因型与CT基因型,差异均有统计学意义（P＜0.05）。结论 MTHFR C677T与脓毒血症患者预后有关,可根据MTHFR C677T的基因多态性预测脓毒血症的预后。     

MTHFR、PITX＿2基因多态性与先天性心脏病的关系探讨

目的探讨5,10-亚甲基四氢叶酸还原酶(MTHFR)、垂体同型框转录因子2(PITX_2)基因多态性与先天性心脏病(CHD)的关系。方法选取2016年5月至2018年6月医院收治的140例CHD患儿,设为病例组,选择140例同期医院产检中心健康围产儿设为健康组。分析并鉴定外周血MTHFR基因C677T位点、PITX_2基因304CG位点基因型分布和等位基因频率,并采用Logistic回归分析法分析C677T、304CG位点多态性与CHD的关系。结果病例组MTHFR基因C677T位点TT基因型构成比高于健康组TT基因型构成比,差异有统计学意义(P0.05),且T等位基因频率高于健康组,差异有统计学意义(P0.05);病例组PITX_2基因304CG位点CC基因型构成比低于健康组CC基因型构成比,差异有统计学意义(P0.05),CG、GG基因型构成比高于健康组,差异有统计学意义(P0.05),且G等位基因频率高于健康组,差异有统计学意义(P0.05);经Logistic回归分析,C677T位点CT、TT基因型及T等位基因可能与CHD发病相关(OR=2.197、3.258、4.509,P=0.006、0.001、0.000),304CG位点CG、GG基因型及G等位基因可能与CHD发病相关(OR=2.546、2.987、3.687,P=0.000、0.000、0.000)。结论 CHD可能与MTHFR基因C677T位点、PITX_2基因304CG位点基因多态性有关。     

Analysis of seven maternal polymorphisms of genes involved in homocysteine/folate metabolism and risk of Down syndrome offspring.

PURPOSE: We present a case-control study of seven polymorphisms of six genes involved in homocysteine/folate pathway as risk factors for Down syndrome. Gene-gene/allele-allele interactions, haplotype analysis and the association with age at conception were also evaluated. METHODS: We investigated 94 Down syndrome-mothers and 264 control-women from Campania, Italy. RESULTS: Increased risk of Down syndrome was associated with the methylenetetrahydrofolate reductase (MTHFR) 1298C allele (OR 1.46; 95% CI 1.02-2.10), the MTHFR 1298CC genotype (OR 2.29; 95% CI 1.06-4.96), the reduced-folate-carrier1 (RFC1) 80G allele (1.48; 95% CI 1.05-2.10) and the RFC1 80 GG genotype (OR 2.05; 95% CI 1.03-4.07). Significant associations were found between maternal age at conception > or = 34 years and either the MTHFR 1298C or the RFC 180G alleles. Positive interactions were found for the following genotype-pairs: MTHFR 677TT and 1298CC/CA, 1298CC/CA and RFC1 80 GG/GA, RFC1 80 GG and methylenetetrahydrofolate-dehydrogenase 1958 AA. The 677-1298 T-C haplotype at the MTHFR locus was also a risk factor for Down syndrome (P = 0.0022). The methionine-synthase-reductase A66G, the methionine-synthase A2756G and the cystathionine-beta-synthase 844ins68 polymorphisms were not associated with increased risk of Down syndrome. CONCLUSION: These results point to a role of maternal polymorphisms of homocysteine/folate pathway as risk factors for Down syndrome.     

A second common variant in the methylenetetrahydrofolate reductase (MTHFR) gene and its relationship to MTHFR enzyme activity, homocysteine, and cardiovascular disease risk

Molecular defects in genes encoding enzymes involved in homocysteine metabolism may account for mild hyperhomocysteinemia, an independent and graded risk factor for cardiovascular disease (CVD). We examined the relationship of two polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, the 677C-->T and 1298A-->C variants, to MTHFR activity, homocysteine concentrations, and risk of CVD in a population of 190 vascular disease patients and 601 apparently healthy controls. The mean specific and residual MTHFR activities were significantly lower in 677CT and 677TT individuals (both P<0.001). The 1298A-->C mutation alone showed no effect on MTHFR activities. However, when the 677C-->T genotype was taken into account, the 1298A-->C mutation also caused a significant decrease in MTHFR activities, which was observed in both the homozygous 1298CC (P<0.001) and the heterozygous 1298AC states (P=0.005). Both the 677TT as the 677CT genotypes were associated with significantly higher fasting and postload homocysteine levels than 677CC (P<0.001 and P=0.003, respectively). The 1298A-->C mutation had no effect on fasting or postload homocysteine levels. Since homocysteine itself is considered to be positively associated with the risk of CVD, these findings indicate that the 1298A-->C mutation cannot be considered a major risk factor for CVD.     

Polymorphisms of methylenetetrahydrofolate reductase gene among women of childbearing age from Shiyan areaCSCD

Objective: To assess the association of methylenetetrahydrofolate reductase (MTHFR) gene 677C>T polymorphism with blood homocysteine (Hey) level among women of childbearing age from Shiyan area. Methods: PCR - chip hybridization was used to determine the genotype of MTHFR 6770T, and a biochemical assay was used to determine the total Hey level among 428 healthy women of childbearing age. Association of MTHFR 677>T with total Hey level was assessed. Results: Heterozygous CT mutation was most common form for the MTHFR 677>T polymorphisms and amounted for 49. 77% among the group, while the CC wild type and homozygous TT mutation respectively accounted for 30. 61% and 19. 63%. These gave a frequency of 44. 51% for the 677T allele. The dominant genotype among different age groups were the CT type. Of note, the proportion of MTHFR 677CC is higher in women above 30 years of age. The distribution of MTHFR 677>T genotypes has differed significantly among different age groups (P<0. 05). Compared with those with wild type alleles, carriers of MTHFR mutations had a higher plasma Hey level. The genotypic frequencies of MTHFR C677T in Shiyan region differed significantly from those of Sichuan, Hebei, Henan and Shandong (P < 0. 05) but were similar to those of Jiangsu, Guangdong, Ningxia and Xinjiang. Conclusion: The distribution of MTHFR C677T polymorphism among women of childbearing age in Shiyan area is influenced by age and is geographically specific and associated with plasma Hey level. Nearly 50% of women have carried the high risk alleles, for whom folic acid supplementation is crucial for the reduction of birth defect rate. © 2018 MeDitorial Ltd. All rights reserved.     

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.     

Infant C677T mutation in MTHFR,maternal periconceptional vitamin use,and cleft lip

Studies have reported an association between homozygosity for a variant form of the methylenetetrahydrofolate reductase (MTHFR) gene and risk for neural tube defects. Because of MTHFR's involvement with folate metabolism and evidence that maternal use of a multivitamin with folic acid in early pregnancy reduces risk for cleft lip with or without cleft palate (CLP), we hypothesized that infants homozygous for the C677T genotype would be at increased risk for CLP because of lower MTHFR enzymatic activity. Data were derived from a large population-based, case-control study of fetuses and liveborn infants among a cohort of 1987 to 1989 California births. The analyses involved 310 infants with isolated CLP whose mothers completed a telephone interview and whose DNA was available from newborn screening blood specimens and involved 383 control infants without a congenital anomaly whose mothers completed a telephone interview and whose DNA was available. Cases and controls were genotyped TT if homozygous for the C677T allele, CT if heterozygous for the C677T allele, and CC if homozygous for the C677 (wild-type) allele. Odds ratios for CLP were 0.89 (0.55 to 1.4) and 0.78 (0.56 to 1.1) for infants with TT versus CC and infants with CT versus CC genotypes, respectively. Compared with the CC genotype, the odds ratios for CLP among infants with the TT genotype were 0.74 (0.39 to 1.4) for those infants whose mothers were users and 1.4 (0.54 to 3.6) for those infants whose mothers were not users of multivitamins containing folic acid periconceptionally. The two estimates were not statistically heterogeneous (P = 0.30). Our results did not indicate increased risks for CLP among infants homozygous for the C677T genotype, nor do they indicate an interaction between infant C677T genotype and maternal multivitamin use on the occurrence of CLP. Am. J. Med. Genet. 80:196–198, 1998. © 1998 Wiley-Liss, Inc.     

Folate gene polymorphisms and the risk of Down syndrome pregnancies in young Italian women

Maternal impairments in folate metabolism and elevated homocysteinemia are known risk factors for having a child with Down syndrome (DS) at a young age. The 80G>A polymorphism of the reduced folate carrier gene (RFC-1) has been recently demonstrated to affect plasma folate and homocysteine levels, alone or in combination with the 677C>T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene. We performed the present study on 80 Italian mothers of DS individuals, aged less than 35 at conception, and 111 Italian control mothers, to study the role of the RFC-1 80G>A, MTHFR 677C>T, and MTHFR 1298A>C genotypes to the risk of a DS offspring at a young maternal age. When polymorphisms were considered alone, both allele and genotype frequencies did not significantly differ between DS mothers and control mothers. However, the combined MTHFR677TT/RFC-1 80GG genotype was borderline associated with an increased risk (OR 6 (CI 95%: 1.0-35.9), P = 0.05), and to be MTHF1298AA/RFC-1 80(GA or AA) was inversely associated with the risk (OR 0.36 (CI 95%: 0.14-0.96), P = 0.04). Present results seem to indicate that none of the RFC-1 80G>A, MTHFR 677C>T, and MTHFR 1298A>C polymorphisms is an independent risk factor for a DS offspring at a young maternal age; however, a role for the combined MTHFR/RFC-1 genotypes in the risk of DS pregnancies among young Italian women cannot be excluded.     

5，10-亚甲基四氢叶酸还原酶基因C677T多态性与先天性心脏病关系的Meta分析

目的对5,10-亚甲基四氢叶酸还原酶（MTHFR）基因C677T多态性与先天性心脏病（CHD）的相关性研究进行Meta分析。方法制定原始文献的纳入标准及检索策略,检索PubMed、EMBASE、Ovid、Springer、中国期刊全文数据库、维普中文科技期刊数据库、万方数据库和中国生物医学文献数据库（1994年1月至2009年1月）中的文献,收集MTHFR基因C677T多态性与CHD相关性的病例一对照研究,剔除不符合要求的文献,应用RevMan4．2软件进行Meta分析,得出合并后的OR值及其95％CI。结果共18篇文献符合纳入标准进入Meta分析。数据合并结果显示,子代MTHFR基因677位点TT／CC和（TT＋CT）／CC与CHD易感性有统计学意义,OR值（95％CI）分别为1．55（1．24～1．93）和1．23（1．06～1．42）,P〈0．05;子代MTHFR基因677位点CT／CC与CHD易感性无统计学意义,OR值（95％CI）为1．15（0．99—1．34）,P〉0．05。父亲MTHFR基因677位点TT／CC和（TT＋CT）／CC与子代CHD的易感性有统计学意义,OR值（95％CI）分别为1．84（1．23～2．74）和1．33（1．04～1．71）,P〈0．05;父亲MTHFR基因677位点CT／CC与子代CHD易感性无统计学意义,OR值（95％CI）为1．25（0．96～1．62）,P〉0．05。母亲MTHFR基因677位点TWCC、CT／CC和（TT＋CT）／CC与子代CHD易感性均无统计学意义,OR值（95％CI）分别为1．20（0．92-1．56）、1．03（0．86～1．24）和1．07（0．90—1．27）,P均〉0．05。传递不平衡分析未发现在CHD核心家系的MTHFR基因677位点存在突变的传递不平衡现象,OR值为0．90（95％CI：0．79～1．12）,P〉0．05。结论子代MTHFR基因677位点TT和TT＋CT为CHD的危险因素之一;父亲MTHFR基因677位点TT和TT＋CT是子代CHD的危险因素之一;母亲MTHFR基因677位点多态性与子代CHD的发生无关。     

糖尿病视网膜病MTHFR基因多态性及其与血浆同型半胱氨酸水平的关系

目的：研究亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）基因多态性及血浆同型半胱氨酸水平与2型糖尿病视网膜病的关系。方法：应用聚合酶链反应－限制性内切酶片段长度多态性技术检测208例2型糖尿病患者（其中110例伴视网膜病）及57名正常对照的MTHFR C677T基因型，采用高效液相色谱法测定血浆同型半胱氨酸水平。结果：糖尿病视网膜病组MTHFR基因TT纯合基因型、CT杂合基因型及T等位基因频率（分别为28．18％、41．82％、49．09％）均明显高于糖尿病不伴视网膜病组（分别为18．37％、29．59％、33．16％）及正常对照组（分别为17．54％、28．07％、31．58％），基因型和等位基因频率分布差异均有显著性（P＜0．01），而MTHFR基因多态性在糖尿病不伴视网膜病组与正常对照组之间差异无显著性（P＞0．05），T等位基因与糖尿病视网膜病的发生密切相关（OR＝1．94，95％CI；1．31－2．88）。糖尿病视网膜病组、糖尿病不伴视网膜病组及正常对照组中，MTHFR基因有C677T突变者血浆同型半胱氨酸水平均显著高于无基因突变者。结论：MTHFR基因C677T位碱基突变致血浆同型半胱氨酸水平升高可能是糖尿病视网膜病发病的重要遗传因素。     

青岛地区汉族育龄妇女亚甲基四氢叶酸还原酶基因667位点多态性分布研究

目的探讨亚甲基四氢叶酸还原酶（MTHFR）基因667位点多态性在青岛市汉族育龄妇女中的分布状况。方法用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）技术检测98份育龄妇女外周血MTHFR C667T基因型分布。结果本研究人群MTHFR 677位点基因的CC、CT、TT基因型频率分别为24.5%、53.1%、22.4%,T等位基因频率为0.49。结论青岛市汉族育龄妇女MTHFR基因667位点多态性与其他地区有较大不同,调查可以为相关研究提供相应的分子生物学依据。