精子Tektin-2基因单核苷酸多态性与特发性弱精子症的相关性研究

目的探讨Tektin-2基因的单核苷酸多态性(SNP)位点rs12043423与特发性弱精子症的相关性。方法采用病例对照法,随机选取特发性弱精子症患者192例作为弱精子症组,另募集同期208例精子活力正常的不育男性作为不育症组和213例精液正常的已生育男性作为正常对照组,所有研究对象均进行精液分析,对三组患者Tektin-2基因的SNP位点rs12043423进行基因分型,比较三组间的基因型和等位基因频率,并且进行与特发性弱精子症的关联分析。结果(1)弱精子症组Tektin-2基因的SNP位点rs12043423的CC基因型频率显著低于正常对照组及不育症组,TT基因型频率则显著增加(P<0.05),而CT基因型频率在三组间的分布频率无显著性差异(P>0.05)。弱精子症组C等位基因的分布频率显著低于正常对照组和不育症组,而T等位基因的频率显著高于正常对照组和不育症组(P<0.05)。不育症组和正常对照组比较,不同基因型的分布频率及等位基因的频率在两组间均无显著性差异(P>0.05)。(2)弱精子症组与正常对照组比较,Tektin-2基因突变(杂合子[CT]和纯合子[TT])的发生率为61.5%vs.50.2%,TT基因型与弱精子症的风险因素分析结果为[OR=1.968,95%CI(1.041,3.723),P=0.035];弱精子症与不育症组比较,Tektin-2基因突变(CT+TT)的发生率为61.5%vs.51.5%,TT基因型与弱精子症的风险因素分析结果为[OR=1.918,95%CI(1.014,3.630),P=0.043]。结论Tektin-2基因rs12043423的多态性位点TT基因型和T等位基因增加特发性弱精子症的易感性,在特发性弱精子症的发展中可能是危险因素。     

特发性无精子症和少精子症患者谷胱甘肽S-转移酶T1基因的遗传多态性

目的:探讨谷胱甘肽S-转移酶T1基因多态性(GSTT1)与特发性无精子症和少精子症的关系。方法:按WHO手册标准,采用WLJY-9000伟力彩色精子质量检测系统对研究对象进行精液分析,根据精液检测结果将研究对象分成特发性无精子症组(n=34)、少精子症组(n=40)和正常对照组(n=53),各组研究对象年龄、吸烟史、饮酒史无统计学差异。基因组DNA来自研究对象提供的外周血有核细胞,采用聚合酶链反应(PCR)方法对研究对象GSTT1基因进行分型。结果:特发性无精子症组、少精子症组GSTT1缺失型基因频率分别为76.5%和72.5%,明显高于正常对照组(49.1%),差异有统计学意义(无精子症组vs正常对照组,OR=3.13,95%CI为1.20～8.16,P=0.020;少精子症组vs正常对照组,OR=2.53,95%CI为1.06～6.11,P=0.038)。结论:GSTT1基因多态性与特发性无精子症、少精子症有相关性;GSTT1缺失基因型是特发性无精子症和少精子症发病的危险因素。     

特发性无精子症和严重少精子症患者Y染色体基因微缺失研究

目的:研究Y染色体基因微缺失与特发性无精子症和严重少精子症的关系,及探讨Y染色体基因微缺失的位点、缺失率有无民族间的差异性.方法:应用多重实时荧光定量聚合酶链反应(PCR)法,对40例汉族及维吾尔族特发性无精子和严重少精子症患者进行Y染色体Azoospermia Factor(AZF)因子多位点的微缺失检测.结果:23例特发性无精子患者中,3例发生AZF因子缺失,缺失率为13.04%;17例严重少精子症患者中,2例发生AZF因子缺失,缺失率为11.76%.结论:Y染色体AZF因子微缺失的范围和位置对于胞质内体外受精治疗男性不育具有重要意义,但Y染色体AZF因子的缺失的位点及缺失率有无民族间的差异性,值得进一步研究.     

XPC基因多态性与男性不育的相关性研究

目的:位于XPC基因外显子区域Ala499Val(C>T)和Lys939Gln(A>C)两个非同义突变的单核苷酸多态性位点在人群中研究广泛,具有潜在的功能性,其多态的变化影响到XPC基因的结构和功能,进而影响到DNA损伤修复率。本文探讨了这两个位点基因多态性在中国汉族人群中的分布及其与男性不育发病风险的关联。方法:采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法,分析318例男性不育患者和228例正常对照男性中XPC基因两个多态性位点的基因分型和等位基因频率,以及这两个位点单独和联合作用与男性不育的相关性。结果:在Ala499Val(C>T)多态性位点中,CC、CT、TT三种基因型频率在病例和对照组中的分布存在显著性差异(P=0.020)。携带TT基因型的个体罹患男性不育的风险是CC基因型个体的0.49倍(95%CI=0.23～0.88),是(CC+CT)基因型个体的0.39倍(95%CI=0.22～0.71)。Lys939Gln(A>C)多态性位点与男性不育的患病风险无显著性关联。联合两个位点分析,个体携带1～4个危险位点患男性不育的风险是携带零个的2.75倍(95%CI=1.50～5.04)。结论:XPC基因Ala499Val(C>T)基因多态性与男性不育的发病风险存在关联,可能是我国汉族人群男性不育的遗传易感因素之一。     

超氧化物歧化酶2基因rs4880位点单核苷酸多态性与男性不育发病风险的相关性研究

目的:探讨超氧化物歧化酶2(SOD2)基因rs4880位点单核苷酸多态性与男性不育发病风险的相关性。方法:采用病例-对照研究的方法,选取519例特发性男性不育患者作为病例组,年龄19~40(28.92±4.37)岁,并按精子浓度和前向运动(PR)精子百分率分为无精子症组(n=143)、严重少精子症组(n=175)、少精子症组(n=89)和弱精子症组(n=112)4个亚组;以338例正常生育的男性作为对照组,年龄19~40(28.40±4.25)岁,进行临床数据的采集。用Sequenom Mass Array技术对SOD2 rs4880位点进行基因分型,用Logistic回归模型分析SOD2 rs4880位点不同基因型与男性不育之间的关系。结果:病例组与正常对照组FSH、PR精子百分率、精子浓度存在显著差异(P0.01)。与野生型纯合TT比较,杂合突变型TC(OR=0.90,95%CI:0.65~1.25,P=0.516)与纯合突变型CC(OR=1.49,95%CI:0.38~5.81,P=0.566)均显示与男性不育无相关性;亚组分析中均显示该基因位点与男性不育不存在相关性:无精子症组中,TC/TT(OR=0.99.95%CI:0.62~1.58,P=0.967),CC/TT(OR=1.58,95%CI:0.26~9.59,P=0.619;严重少精子症组中,TC/TT(OR=1.07.95%CI:0.70~1.64,P=0.750),CC/TT(OR=1.31,95%CI:0.22~7.96,P=0.767;少精子症组中,TC/TT(OR=0.83.95%CI:0.47~1.48,P=0.535),CC/TT(OR=1.22,95%CI:0.13~11.90,P=0.865);弱精子症组中,TC/TT(OR=0.59.95%CI:0.33~1.05,P=0.074),CC/TT(OR=1.84,95%CI:0.30~11.16,P=0.510)。结论:SOD2 rs4880位点基因多态性与男性不育不存在相关性,但是由于实验样本条件的限制,需要更大的样本量以及样本选取范围来进一步研究验证。     

特发性无精子症和严重少精子症患者Y染色体基因微缺失分析

目的：研究Y染色体基因微缺失与特发性无精子症和严重少精子症的关系，并建立一个灵敏、操作简便的分子检测方法。方法：应用实时荧光定量聚合酶链反应(PCR)法对65例特发性无精子症患者、27例严重少精子症患者进行Y染色体YRRM1、DAZ、DYS1基因微缺失的检测。结果：65例特发性无精子症患者中，3例发生YRRM1基因微缺失，发生率为4．6％；5例发生DAZ基因微缺失，发生率为7．7％。27例严重少精子症患者中，1例发生YRRM1基因微缺失，发生率为3．7％；2例发生DAZ基因微缺失，发生率为7．4％。92例患者中均未发现DYS1基因微缺失。结论：YRRM1和DAZ基因位点的微缺失与特发性无精子症和严重少精子症有一定的相关性，DYS1基因缺失与男性生精障碍的相关性仍需进一步研究明确。应用荧光定量PCR法检测Y染色体微缺失具有灵敏、快速、操作简便的特点。     

DAZL基因单核苷酸多态性与弱畸精子症的相关性研究

目的:探讨DAZL基因(deleted in azoospermia like)单核苷酸多态性(SNP)与弱精子症伴畸形精子症男性不育的关系。方法:收集弱畸精子症不育患者(病例组,n=173)和精液正常男性(对照组,n=175)精液样本,进行精液常规及精子形态学分析并提取精子基因组DNA,应用Sequenom MassARRAY SNP分型技术对DAZL基因A260G和A386G多态性位点进行基因分型,比较病例组与对照组基因型的分布差异。结果:在病例组与对照组中,DAZL基因A260G、A386G这两个位点均表现为野生基因型,无突变基因型。结论:DAZL基因A260G和A386G两个多态性位点与汉族男性精子活力低下及精子形态异常所致不育可能不存在相关,不足以视为男性不育的易感基因。     

186例少弱精子症患者MTHFR C677T基因多态性观察

目的观察186例少弱精子症男性不育患者的亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性的分布及频率。方法以186例少弱精子症的男性不育患者为不育组,同期就诊的有正常生育史和精液参数正常的男性131例为对照组,比较两组男性MTHFR C677T基因多态性的分布及频率差异。结果不育组中MTHFR基因CC基因型分布频率显著低于对照组(36.6%vs.55.0%,P<0.05),TT型分布频率则显著高于对照组(20.4%vs.13.7%,P<0.05),T等位基因的分布频率亦显著高于对照组(41.9%vs.29.4%,P<0.05)。结论 MTHFR基因C677T多态性可能与男性少弱精子症的发生相关,可能是造成男性不育的一个遗传学因素。但因本研究纳入的观察对象数量有限,结论存在一定的局限性,后续尚需更深入的研究探讨。     

无精子症和严重少精子症DYS240基因位点的分析

无精子因子的缺乏将导致无精子症和严重少精子症。本研究应用ＰＣＲ方法分析了６５例核型正常的无精子症和２５例核型正常的严重少精子症病人的ＤＹＳ２４０基因位点，结果显示，无精子症病人中６例缺乏ＤＹＳ２４０基因位点，严重少精子症病人中４例缺乏ＤＹＳ２４０基因位点，提示ＤＹＳ２４０基因是ＡＺＦ的一个重要的候选成分。     

SPO11基因单核苷酸多态性与陕西回族人群非梗阻性无精症相关性研究

目的探讨SPO11基因单核苷酸多态性在陕西回族非梗阻性无精症人群中的分布及其与无精症发病风险的关联。方法采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法,分析40例陕西回族非梗阻性无精症患者和45例陕西回族正常对照男性SPO11基因SNP位点（rs28368082）的基因分型和等位基因频率,以及其与非梗阻性无精症发病的相关性。结果 SPO11基因SNP位点（rs28368082）的CC,CT两种基因型频率在病例和对照组中分布存在显著性差异（P=0.048）,携带CT基因型的个体患非梗阻性无精症的风险是CC基因型的7.76倍（95%CI=0.89～66.58）。结论SPO11基因SNP位点（rs28368082）与陕西回族人群非梗阻性无精症发病风险存在关联,可能是陕西回族人群非梗阻性无精症的遗传易感基因之一。     

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.     

XPC gene polymorphisms and risk of idiopathic azoospermia or oligozoospermia in a Chinese population

A retrospective case–control study was carried out in the Han-Chinese population to determine the polymorphisms of xeroderma pigmentosum complementation group C ( XPC ) gene on the risk of idiopathic azoospermia or oligozoospermia. The Ala499Val (C>T) and Lys939Gln (A>C) polymorphism of XPC gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism in three groups of infertile men (172 patients of azoospermia, 25 patients of severe oligozoospermia, 55 patients of oligozoospermia) and 228 fertile men. Increased risk of idiopathic azoospermia, but not oligozoospermia was associated with the XPC variant genotypes of Ala499Val (C>T) [adjusted odds ratio (OR) = 1.67, 95% confidence interval (CI) = 1.04–2.68 for CT heterozygote and adjusted OR = 2.03, 95% CI = 1.10–3.75 for TT homozygote] compared with CC homozygous wide-type. The Lys939Gln (A>C) polymorphism was not related to spermatogenic failure. The combined risk alleles analysis and haplotype analysis showed that ORs increased as the number of the risk alleles increased and the 499T-939C haplotype had a significantly increased risk of idiopathic azoospermia (OR = 7.97; 95% CI = 3.51–18.07) compared with other haplotypes. The results suggest that XPC Ala499Val (C>T) polymorphism is correlated with high risk of idiopathic azoospermia in the Han-Chinese population.     

Association between MTHFR C677T polymorphism and diabetic nephropathy in the Chinese population: An updated meta‐analysis and review

To clarify the effects of MTHFR C677T polymorphism on the risk of diabetic nephropathy (DN) in the Chinese population, an updated meta‐analysis was performed. Related studies were identified from PubMed, Springer Link, Ovid and Chinese Databases up to 24 February 2015. A total of 15 studies including 1227 DN cases, 586 healthy controls and 1277 diabetes mellitus (DM) controls were involved in this meta‐analysis. Overall, a significantly elevated risk of DN was associated with all variants of MTHFR C677T when compared with the healthy group (T vs C, odds ratio (OR) = 2.22, 95% confidence interval (CI) = 1.88–2.61; TT vs CC, OR = 4.22, 95% CI = 3.02–5.90; TT + CT vs CC, OR = 2.62, 95% CI = 2.07–3.31; TT vs CC + CT, OR = 2.81, 95% CI = 2.08–3.81) or DM (T vs C, OR = 1.78, 95% CI = 1.59–2.00; TT vs CC, OR = 2.95, 95% CI = 2.33–3.73; TT + CT vs CC, OR = 1.93, 95% CI = 1.63–2.29; TT vs CC + CT, OR = 2.31, 95% CI = 1.87–2.84). In subgroup analyses stratified by ethnicity and geographic areas, it revealed the significant results in Chinese Han, in North and South China. The risk conferred by MTHFR C677T polymorphism is higher in North China than in South China. This meta‐analysis showed that the MTHFR C677T variants may influence DN risk in Chinese, and further studies with gene–gene and gene–environment interactions are required for definite conclusions.     

IL‐16 polymorphism and risk of renal cell carcinoma: Association in a Chinese population

Objectives: Interleukin‐16 (IL‐16) plays a fundamental role in inflammatory diseases, as well as in the development and progression of tumors. A T‐to‐C polymorphism at the ‐295 position in the promoter region of the IL‐16 gene has been described. This variation might lead to altered IL‐16 expression, and might modulate an individual's susceptibility to cancer. The objective of the present study was to determine if IL‐16 polymorphism is associated with risk of renal cell carcinoma (RCC). Methods: A case–control study including 335 RCC cases and 340 cancer‐free controls was carried out. All subjects were genetically unrelated ethnic Han Chinese recruited from a single institution between July 2006 and July 2009. The IL‐16 ‐295 T>C polymorphism was determined by using the polymerase chain reaction‐restriction fragment length polymorphism method. Serum samples were available for 70 RCC cases and 96 controls to detect IL‐16 concentration. Results: Compared with the IL‐16 ‐295 TT genotype, the CC genotype had a significantly decreased RCC risk (adjusted odds ratio [OR] = 0.34, 95% confidence interval [CI] = 0.18–0.66). Furthermore, a significant decreased risk of RCC was found in the combined variant genotypes CT + CC compared with the TT genotype (adjusted OR = 0.68, 95% CI = 0.50–0.93). In addition, the serum IL‐16 levels in RCC patients were significantly lower than those in controls (P < 0.001). Furthermore, patients carrying CC genotype or CT genotype had higher serum IL‐16 levels than TT carriers. Conclusion: IL‐16 ‐295 T>C polymorphism is significantly associated with a higher risk of developing RCC in Chinese population.     

DNA损伤修复基因XRCC1 Arg194Trp基因多态性与中国人群结直肠癌易感性的Meta分析

【摘要】 目的 探讨DNA损伤修复基因XRCC1 Arg194Trp基因多态性与中国人群结直肠癌易感性的关系。方法 按照制定的检索策略,通过计算机和手工检索相关数据库,收集有关XRCC1 Arg194Trp基因多态性与中国人群结直肠癌易感性的病例对照研究,按照纳入标准筛选文献、并从纳入文献中提取相关数据,以病例组和对照组基因型分布的比值比(OR)为效应指标,应用Stata12.0软件进行异质性检验,对各研究原始数据进行Meta合并,并行敏感性分析和发表偏倚的评估。结果〓本Meta分析共纳入11项病例对照研究,累积病例2710例,对照3567例。根据各研究间的异质性,采用不同的模型进行合并效应量。在等位基因比较(T vs C) [OR(95%CI)=1.18(1.01-1.39),P=0.036],纯合子比较模型(TT vs CC) [OR (95%CI)=1.39(1.02-1.90),P=0.038],显性模型(CT/TT vs CC) [OR(95%CI)=2.24(1.78-2.82),P<0.001] 以及隐性模型 (TT vs CT/CC) [OR(95%CI)=1.23(1.02-1.49),P=0.030]均存在显著的统计学差异。发表偏倚评估均未见明显偏倚。结论〓在中国人群中,携带突变等位基因T或突变纯合子TT的人群罹患CRC的风险有所升高,而在显性遗传模型中,携带有CT/TT基因型的人群其CRC的易感性明显升高。     

MicroRNA-34b/c rs4938723 T>C多态性与中国汉族人群肾细胞癌易感性的相关性

目的研究中国汉族人群microRNA-34b/c启动子区TC(rs4938723)多态性与肾细胞癌易感性之间的关系。方法采用病例对照研究模式,通过TaqMan探针PCR法检测年龄和性别匹配的710例中国汉族人群肾细胞癌患者和760例正常人群的microRNA-34b/c启动子区TC(rs4938723)基因型,探讨该位点基因多态性与肾细胞癌易感性之间的关系。结果与TT/TC基因型携带者相比,CC型(OR=1.53,95%CI=1.06~2.21,CC基因型比TT基因型;OR=1.48,95%CI=1.05~2.10,CC基因型比TT/TC基因型)携带者发生肾细胞癌的危险性明显升高。分层分析显示携带CC基因型的老年患者(OR=1.80,95%CI=1.08~3.01)、男性患者(OR=1.64,95%CI=1.08~2.51)、吸烟患者(OR=2.07,95%CI=1.16~3.69)及饮酒患者(OR=1.94,95%CI=1.01~3.73)发生肾细胞癌的危险性明显升高。结论 microRNA-34b/c启动子区TC(rs4938723)基因多态性与我国汉族人群肾细胞癌易感性有关,CC型携带者发生肾细胞癌的危险性要明显高于TT/TC型携带者。     

eNOS gene T786C,G894T and 4a4b polymorphisms and male infertility susceptibility: a meta‐analysis

The association between polymorphism of eNOS and male infertility in several studies was controversial. To explore a more precise estimation of the association, a meta‐analysis of eight case–control studies, including 1,968 cases and 1,539 controls, were selected. The meta‐analysis was conducted by calculating the pooled odds ratio (OR) with a 95% confidence interval (95% CI). Overall, the association between T786C and risk of male infertility was obvious (TC vs. TT: OR, 1.20; 95% CI, 1.01–1.42; CC vs. TT: OR, 3.37; 95% CI, 1.65–6.87; TC/CC vs. TT: OR, 1.47; 95% CI, 1.25–1.73; CC vs. TT/TC: OR, 3.18; 95% CI, 1.54–6.56; TC vs. TT: OR, 1.65; 95% CI, 1.27–2.03). However, no overall association was observed between the other two polymorphisms of eNOS (G894T and 4a4b) and male infertility. Stratified analysis showed that significantly strong association between T786C polymorphism and semen quality was present in all three types of male infertility (azoospermia, oligozoospermia and asthenozoospermia). In the subgroup analysis based on ethnicity, both T786C and 4a4b could influence the risk of male infertility in Asian and Caucasian. Further studies of polymorphisms of eNOS with their biological functions are needed to understand the role in the development of male infertility.     

Association of the methylenetetrahydrofolate reductase gene C677T polymorphism with the risk of male infertility: a meta-analysis

Several molecular epidemiological studies have been conducted to examine the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and male infertility susceptibility, but the results remain inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. In this meta-analysis, a total of 26 case–control studies including 5659 infertility cases and 5528 controls were selected to evaluate the possible association. The pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to assess the strength of association of C677T polymorphism with male infertility in the additive model, dominant model, recessive model and allele-frequency genetic model. In the overall analysis, the frequency of the 677T allele was significantly associated with male infertility susceptibility (OR?=?2.32, 95%CI?=?2.04–2.65 for TT vs. CC genotype; OR?=?1.09, 95%CI?=?1.00–1.19 for CT vs. CC genotype; OR?=?1.19, 95%CI?=?1.10–1.29 for CT/TT vs. CC genotype; OR?=?1.54, 95%CI?=?1.36–1.74 for TT vs. CC/TT genotype; OR?=?1.22, 95%CI?=?1.15–1.30 for T vs. C allele). A subgroup analysis of the subjects showed that significantly strong association between MTHFR C677T polymorphism and male infertility was present only in Asians, but not in Caucasians. Additionally, MTHFR C677T was associated with a significant increase in the risk of azoospermia in all genetic models. Meanwhile, no significantly increased risks of oligoasthenotertozoospermia (OAT) were found in most of the genetic models. In conclusion, this meta-analysis is in favor that the MTHFR C677T polymorphism is capable of causing male infertility susceptibility, especially in Asians and the subgroup of azoospermia.     

Genetic polymorphism of glutathione S-transferase T1 gene and susceptibility to idiopathic azoospermia or oligospermia in northwestern China

Aim： To investigate the association of glutathione S-transferase T1 （GSTT1） gene polymorphism in patients with idiopathic azoospermia or oligospermia in the northwestern China population. Methods： In the case-control study, GSTT1 genotypes were identified by multiplex polymerase chain reaction （PCR） with peripheral blood DNA samples from 78 patients with idiopathic azoospermia, 103 patients with idiopathic oligospermia and 156 age-matched controls with normal sperm concentration and motility, according to the criteria adapted from World Health Organization guidelines. All of the patients and controls were from northwestern China. Results： There is a significant association between GSTT1 null genotype with idiopathic azoospermia risk （odds ratio [OR]： 2.36, 95% confidence interval [CI]： 1.33-4.20, P = 0.003） or idiopathic oligospermia risk （OR： 2.00, 95% CI： 1.17-3.27, P = 0.010）. Conclusion： GSTT1 null genotype is a predisposing risk factor for sporadic idiopathic azoospermia or oligospermia in northwestern China. （Asian J Androl 2008 Mar; 10： 266-270）     

Methylenetetrahydrofolate reductase C677T polymorphism and the risk of male infertility: a meta-analysis

Several molecular epidemiological studies have been conducted to examine the association between MTHFR C677T polymorphism and male infertility susceptibility, but the results remain inconsistent. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 10 case-control studies, including 2275 cases and 1958 controls, were selected. Crude odds ratios (ORs) with 95% confidence intervals were used to assess the strength of association in the additive model, dominant model and recessive model. In the overall analysis, no significant association between the polymorphism and risk of male infertility was observed. Stratified analysis showed that significantly strong association between MTHFR C677T polymorphism and male infertility were present only in Asians (OR = 1.79 for TT vs. CC genotype; OR = 1.42 for CT/TT vs. CC genotype; OR = 1.50 for TT vs. CC/CT genotype; OR = 1.36 for T vs. C allele), but not in Caucasians. Additionally, MTHFR 677T was associated with a significant increase in the risk of azoospermia in all genetic models. No significantly increased risks of oligoasthenoteratozoospermia were found in any of the genetic models. In conclusion, this meta-analysis supports that MTHFR C677T polymorphism is capable of causing male infertility susceptibility in Asians, but not in Caucasians.