Y染色体AZFc部分缺失和全缺失对精子发生的影响

目的 研究Y染色体AZFc部分缺失(gr/gr缺失、b2/b3缺失)和AZFc全缺失(b2/b4缺失)对精子发生的影响.方法 实验组选择非梗阻性无精子症者458例,对照组选择符合卫生部标准的汉族合格捐精者301例.所有受试者均抽取外周血,抽提DNA,选择Y染色体序列标签位点(STS),经多重PCR技术检测Y染色体AZFc部分缺失与全缺失,对结果进行统计学分析.结果 实验组AZFc部分缺失为:gr/gr缺失41例(8.9%),b2/b3缺失11例(2.4%):AZFc全缺失5例(1.1%).对照组AZFc部分缺失:gr/gr缺失23(8.6%)例, b2/b3缺失7例(2.3%):未发现AZFc全缺失.两组比较,AZFc全缺失差异显著(P＜0.05);AZFc部分缺失(gr/gr缺失、b2/b3缺失)发生率无显著性差异(P＞0.05).结论 汉族男性Y染色体AZFc部分缺失(gr/gr、b2/b3缺失)在非梗阻性无精子症患者和IE常捐精者中都存在,但无统计学意义,不能作为精子发生障碍的危险因子.AZFc全缺失(b2/b4缺失)则引起严重的生精功能障碍,可作为精子发生障碍的危险因子之一.     

Y染色体新缺失类型gr/gr微缺失对精子发生的影响

目的探讨Y染色体新缺失类型gr/gr微缺失对睾丸精子发生的影响。方法选取Y染色体特异性序列标签点(STS),用多重PCR技术检测严重男性不育患者118例,志愿捐精者120例,观察Y染色体gr/gr微缺失情况。不育患者经2次以上精液分析,均为睾丸性无精子症或精子密度<1×106/ml。捐精者均经精液分析和染色体检查,符合卫生部标准的正常男性。追踪分析6例gr/gr微缺失者父亲微缺失情况,其中3例为不育者的父亲,另3例为捐精者的父亲。结果多重PCR检测118例男性不育患者gr/gr微缺失12例(10.2%);120例捐精者gr/gr微缺失11例(9.2%)。2组比较差异无统计学意义(P>0.05)。6例gr/gr微缺失者的父亲均表现gr/gr微缺失。结论Y染色体gr/gr微缺失既存在于严重不育男性,也存在于生精功能正常的捐精者中,gr/gr微缺失可能遗传自父亲,可能未影响精子的发生,不能认为是精子发生的遗传风险因子。     

AZFc区部分缺失与男性不育的关系

Y染色体长臂无精子症因子(AZF)的微缺失是导致男性不育的一个重要原因。在AZF微缺失中以AZFc区的全部缺失(b2/b4缺失)最为常见,近年来的研究发现AZFc区的缺失种类繁多,不仅有AZFc区的全部缺失,还存在AZFc区部分缺失(gr/gr缺失,b1/b3缺失,b2/b3缺失),并且部分缺失也可能与男性不育有关。本文旨在对AZFc区部分缺失的研究进展及与男性不育的关系做一综述。     

无精子症因子缺失与男性不育相关性研究进展

Y染色体上含有与男性性腺发育和精子发生及分化密切相关的基因。无精子症因子(AZF)是位于Y染色体长臂远端的精子发生调控基因,它的缺失会导致精子发生障碍进而引发男性不育。目前大多数人将AZF分为AZFa、AZFb、AZFc三个区域,也有人认为AZFb和AZFc之间应该增加一个新的区域并命名为AZFd。不同分区的缺失会引起不同的表型。其中,AZFc缺失作为目前最常见的缺失类型被广泛的研究。AZFc缺失包括了AZFc全缺失和AZFc部分缺失,AZFc部分缺失主要为gr/gr缺失和b2/b3缺失。gr/gr缺失在某些地区或人种中引起男性生精障碍的作用已经被证实,b2/b3缺失对生精障碍的影响目前尚无定论,但是它在单倍群N中的普遍分布这一现象也引发了人们的深入思考。本文对AZF不同区域尤其是AZFc区的基本结构、候选基因、缺失情况以及与精子发生的关系作一综述,旨在为临床产前诊断及男性不育治疗提供理论依据。     

男性不育病人Y染色体AZFc/DAZ微缺失的实时荧光PCR筛查

目的 :建立一套Y染色体微缺失的实时荧光PCR筛查方法 ,对无精子症或少精子症男性不育病人进行Y染色体AZFc/DAZ微缺失的常规筛查。　方法 :采用实时荧光PCR对进行卵细胞胞质内单精子注射 (ICSI)治疗的 87例无精子症和少精子症病人以及睾丸活检的 30例无精子症病人进行Y染色体AZFc/DAZ微缺失的检测 ,同时用多重PCR作为方法学对照。　结果 :AZFc/DAZ缺失 11例 (9.4%) ,其中 6 1例少精子症病人中发现 4例(6 .6 %) ,5 6例无精子症病人中发现 7例 (12 .5 %)。　结论 :Y染色体AZFc/DAZ微缺失的实时荧光PCR筛查方法是易行和可靠的 ,与多重PCR筛查结果完全一致。     

中国男性不育的重要遗传病因:染色体异常与Y染色体AZFc区DAZ基因拷贝缺失

目的:探讨染色体的结构与数目异常,以及位于Y染色体无精子症因子C区(azoospermiafactorC,AZFc)中无精子症缺失基因家族(deleted-in-azoospermia,DAZ)基因拷贝缺失与男性不育的关系。方法:运用染色体G显带、多重PCR与PCR-RFLP检测技术,对210例已生育男性、247例无精子症与206例严重少精子症患者Y染色体AZF区结构进行分析,并对453例患者进行外周血染色体检查。结果:在无精子症与严重少精子症患者中染色体数目与结构异常发生率分别为12.6%与8.3%。所有已生育男性中未检出DAZ基因全部或部分拷贝缺失,而在无精子症与严重少精子症患者中4个DAZ基因拷贝缺失率分别为7.7%和11.2%,DAZ1/DAZ2共缺失率分别为7.3%和4.9%。结论:在中国男性无精子症与严重少精子症患者中存在较高频率的染色体结构/数目异常与DAZ基因拷贝缺失现象,提示染色体结构/数目异常与Y染色体AZFc区DAZ基因拷贝缺失可能是中国男性不育的重要遗传病因。     

gr/gr和b2/b3缺失中不同DAZ拷贝缺失与精子发生障碍的相关性研究

目的:研究AZFc区gr/gr和b2/b3缺失中DAZ基因拷贝缺失对中国男性精子发生障碍的影响。方法:试验组纳入121例不同程度生精障碍的不育男性,对照组选择了95例健康男性且均符合《WHO人类精液检查与处理实验室手册》第5版标准,通过常规PCR和PCR-RFLP以及Y染色体特异性序列标签位点(STS),分析AZFc区不同类型gr/gr和b2/b3缺失中DAZ基因拷贝缺失与男性精子发生障碍的关系。结果:对照组中共观察到13例(13.68%)gr/gr缺失和1例(1.05%)b2/b3缺失,试验组中发现15例(12.40%)gr/gr缺失及6例(4.96%)b2/b3缺失。DAZ特异性单核苷酸变异位点(SNV)分析显示对照组中有3例(3.16%)gr/gr-DAZ1/DAZ2缺失和10例(10.53%)gr/gr-DAZ3/DAZ4缺失以及1例(1.05%)b2/b3-DAZ3/DAZ4缺失,试验组中有11例(9.09%)gr/gr-DAZ1/DAZ2缺失和4例(3.31%)gr/gr-DAZ3/DAZ4缺失以及6例(4.96%)b2/b3-DAZ1/DAZ2缺失。结论:中国男性Y染色体AZFc部分缺失(gr/gr、b2/b3缺失)在正常生精者和不同程度的生精障碍患者中均存在,且差异无统计学意义,不能作为精子发生障碍的危险因素。但gr/gr和b2/b3缺失中不同类型的DAZ拷贝子缺失对男性精子发生的影响不同,DAZ1/DAZ2缺失与男性生精功能障碍相关,可能是导致男性不育的危险因素,而DAZ3/DAZ4缺失似乎对生精的影响很小或不起作用。     

Y染色体微缺失与男性不育的关系分析

据WHO调查，在育龄夫妇当中约有10％～15％患者不育，其中男性因素约占40％～50％，而精子生成障碍的则占其中的30％。精子生成障碍的原因是多因素的，例如疾病、营养不良、内分泌紊乱、遗传缺陷和环境因素，尤其是遗传缺陷和染色体异常都会引起精子的生成障碍。我院自2003年起，应用多重聚合酶链反应(PCR)对部分男性不育患者进行Y染色体微缺失检测，分析其与男性不育的关系，现报告如下：     

Y染色体微缺失与男性不育研究进展

约 10 %～ 15 %原因不明的无精子症和 5 %～ 10 %严重少精子症存在Y染色体AZF微缺失 ,该不育人群借助ICSI技术可产生子代 ,但同时可将微缺失垂直传播给男性后代引起不育。本文从Y染色体微缺失的频率位置、基因型和表型的关系、缺失的来源机制、检测手段、助孕技术与其关系等几个方面予以综述 ,以进一步理解男性不育的原因 ,从而为诊断、治疗提供一条新途径     

精索静脉曲张男性不育患者Y染色体微缺失检测

目的:探讨精索静脉曲张(varicocele,VC)不育患者Y染色体微缺失特点及其与临床表型的关系,为评价VC不育患者是否行手术治疗或ICSI提供依据。方法:VC不育患者174例,分为3组,A组:无精子症47例;B组:严重少精子症57例;C组:轻度少精子症70例;设立正常生育的健康志愿者男性28例作为对照组(D组)。抽取外周血提取DNA,选取Y染色体上AZFa、AZFb、AZFc区共6个序列标签位点,应用多重PCR进行扩增;已生育女性26例作为阴性对照,分别运用琼脂糖凝胶电泳分离,对照阅读扩增产物,判定有无缺失存在以及缺失类型。结果:174例男性不育患者中有22例检测到Y染色体微缺失,缺失率12.64%;A组11例存在微缺失,B组11例存在微缺失,C组未检测到微缺失。A组与C组、B组与C组比较,差异均有显著性。A组缺失病例中有6例为AZFc区缺失,1例为AZFa缺失,2例为AZFb区缺失,2例为AZFb、AZFc区共同缺失;B组缺失病例中有8例为AZFc缺失,2例为AZFb缺失,1例为AZFb、AZFc区共同缺失。结论:①精液异常VC不育与Y染色体微缺失有关;②VC不育患者特别是无精子症和严重少精子症患者,应该进行Y染色体微缺失的检测。     

AZF microdeletions and partial deletions of AZFc region on the Y chromosome in Moroccan men

Aim： To evaluate for the first time the frequency of Y chromosome microdeletions and the occurrence of the partial deletions of AZFc region in Moroccan men, and to discuss the clinical significance of AZF deletions. Methods： We screened Y chromosome microdeletions and partial deletions of the AZFc region of a consecutive group of infertile men （n = 149） and controls （100 fertile men, 76 normospermic men）. AZFa, AZFb, AZFc and partial deletions of the AZFc region were analyzed by polymerase chain reaction （PCR） according to established protocols. Results： Among the 127 infertile men screened for microdeletion, four subjects were found to have microdeletions： two AZFc deletions and two AZFb＋AZFc deletions. All the deletions were found only in azoospermic subjects （4/48, 8.33%）. The overall AZFc deletion frequency was low （4/127, 3.15%）. AZF microdeletions were not observed in either oligoasthenoteratozoospermia （OATS） or the control. Partial deletions of AZFc （gr/gr） were observed in a total of 7 of the 149 infertile men （4.70%） and 7 partial AZFc deletions （gr/gr） were found in the control group （7/176, 3.98%）. In addition, two b2/b3 deletions were identified in two azoospermic subjects （2/149, 1.34%） but not in the control group. Conclusion： Our results suggest that the frequency of Y chromosome AZF microdeletions is elevated in individuals with severe spermatogenic failure and that gr/gr deletions are not associated with spermatogenic failure.     

Y chromosome variants and male reproductive function

The detailed analysis of the Y chromosome in men with azoospermia or severe oligozoospermia has resulted in the identification of three regions of the long arm of the human Y chromosome, termed AZFa, AZFb and AZFc, (AZF: AZoospermia Factor) that are currently deleted in men with otherwise unexplained spermatogenic failure. Screening for these deletions is now common in many infertility centres and in some instances they have a prognostic relevance. Recently, attention has turned to partial deletions of the AZFc region. At first sight some of these deletions appear to have little effect on fertility, whilst others appear to be associated with significant risk for developing spermatogenic failure. However, the relationship between these partial AZFc deletions, reduced sperm counts and infertility is the subject of a continuing intense debate. There is a pressing need to clarify the impact of partial AZFc deletions on human spermatogenesis. This requires large-scale studies on well-characterized normospermic and oligo/azoospermic individuals of different ethnic origins with multiple informative AZFc markers if the correlation between these deletions and the phenotype is finally to be resolved. The definition of Y chromosome variants (haplotypes) in cases of partial AZFc deletions is likely to play an essential role in understanding the contribution of the deletion to reduced sperm counts.     

Y染色体基因微缺失在严重少精子症和无精子症中的应用

目的 利用Y染色体基因微缺失的检测来明确少精子症、无精子症患者病因.方法 采用多重聚合酶链反应技术,针对31例严重少精子症和9例无精子症患者与对照组41名已正常生育的男性,进行AZFa、AZFb、AZFc、3个区域共12个序列标签位点(sequence tag site,STS)的微缺失分析.结果 严重少精子症31例中发现Y染色体微缺失6例,无精子症9例中发现Y染色体微缺失3例,而正常对照组41例均未发现Y染色体微缺失.此研究中发现缺失形式有2种,分别是AZFa+AZFb+AZFc区的全缺失和AZFc区的单独缺失.结论 Y染色体微缺失与精子发生障碍导致的不育有一定的联系.     

Y染色体及其微缺失与男性不育:过去、现在与将来

由遗传缺陷所引起的精子发生障碍是男性不育的一个重要病因。一直以来,Y染色体被认为缺乏重要的功能基因。直到睾丸决定基因的发现,Y染色体的研究才重新得到重视。Y染色体的成功测序揭开了Y染色体的真实结构和Y染色体微缺失的分子基础。在Y染色体上的220个基因中,位于AZF区的16个编码基因或基因家族与男性生殖与发育相关。至今,在Y染色体AZF区已发现至少12种缺失。Y染色体上大量的同源序列与回文结构所致非等位的同源性重组是Y染色体微缺失发生的分子基础。Y染色体微缺失是已知的导致男性不育的最主要的分子遗传病因,临床上常使用PCR扩增Y染色体特异的序列标记位点来进行检测。基因组学时代的到来为男性不育的研究带来革命性的工具与方法,有利于加深对Y染色体缺失发生机制的了解,进一步明确Y染色体基因的功能以及相互之间的联系,为基因治疗奠定基础。     

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.     

Y-chromosomal.microdeletions and partial deletions of the Azoospermia Factor c （AZFc） region in normozoospermic, severe oligozoospermic and azoospermic men in Sri Lanka

Aim:To assess for the first time the occurrence of Y chromosomal microdeletions and partial deletions of theAzoospermia Factor c(AZFc)region in Sri Lankan men and to correlate them with clinical parameters.Methods:Ina retrospective study,we analyzed 96 infertile men(78 with non-obstructive azoospermia)and 87 controls withnormal spermatogenesis.AZFa,AZFb,AZFc and partial deletions within the AZFc region were analyzed by multiplexpolymerase chain reaction(PCR)according to established protocols,Results:No AZFa,AZFb or AZFc deletionswere found in the control group.Seven patients in the group of infertile men were found to have deletions as following:one AZFa,two AZFc,two AZFbc and two AZFabc.The relative distribution of these patterns was significantlydifferent compared with that found in the German population.Extension analysis confirmed that the deletions oc-curred according to the current pathogenic model.gr/gr deletions were found to be equally present both in the patients(n=4)and in the control group(n=4).One b2/b3 deletion was found in the patient group.Conclusion:Theseresults suggest that the frequency and pattern of microdeletions of the Y chromosome in Sri Lankan men are similarto those found in other populations and confirm that gr/gr deletions are not sufficient to cause spermatogenetic failure.(Asian J Androl 2006 Jan;8:39-44)     

The c.‐190 C>A transversion in promoter region of protamine 1 gene as a genetic risk factor in Egyptian men with idiopathic infertility

Protamines are considered the most important structure in the sperm nucleus, and they are proteins with a significantly large amount of amino acids carrying a positive charge, which allows the formation of the tight package of the genomic DNA in the spermatozoa. Many authors studied the abnormalities in the protamine 1 (PRM1) and/or protamine 2 (PRM2) genes and reported their possible association with male infertility. The chromosome 16 (16p13.2) carries these genes containing multiple undiscovered single nucleotide polymorphisms. The aim of the present study was to investigate the association of c.‐190 C>A transversions that occur in PRM1 with idiopathic infertility in a sample of Egyptian men. It was a case–control study, and blood samples were collected from sixty male patients complaining of idiopathic infertility and forty healthy fertile males. The c.‐190 C>A transversion in promotor region protamine 1 gene (rs2301365) was assessed by 5' nuclease assay, using Rotor‐Gene Q real‐time PCR system. The results of the present study revealed that CA and AA genotypes in PRM1 gene were associated significantly with low sperm concentration and decreased sperm motility (p = 0.001). Cases carrying A allele had a 6.05‐fold increased risk for idiopathic infertility than cases carrying the C allele (OR: 6.05, 95% CI: 2.038–17.98 p statistically significant ≤0.05). Analysis of the results revealed that the c.‐190 C>A transversion may be involved in the development of male infertility.