无精子症、严重少精子症患者染色体核型与Y染色体AZF微缺失的相关性分析

目的对无精子症、严重少精子症患者染色体核型与Y染色体AZF微缺失的相关性进行分析,以探讨Y染色体AZF微缺失检测在男性不育中的应用价值。方法对无精子症、严重少精子症患者进行细胞遗传学分析,根据分析结果分为染色体核型正常组及异常组。采用PCR方法对各样本Y染色体AZF所在区域的6个序列标签位点（STS）进行扩增,琼脂糖凝胶电泳进行扩增产物的检测。结果在所分析的76例无精子症、严重少精子症患者中,染色体核型异常组27例,其中未检测到有Y染色体AZF缺失的存在;染色体核型正常组49例,其中1例无精症患者发现有Y染色体AZF缺失的存在。结论染色体核型异常与AZF微缺失无相关性。Y染色体AZF微缺失是造成男性不育的原因之一。Y染色体AZF微缺失检测在无精子症、严重少精子症患者中具有重要价值,可明确无精子症、严重少精子症的病因,从而避免不必要的治疗。     

424例非梗阻性无精子症和严重少精子症患者的细胞与分子遗传学研究

目的探讨非梗阻性无精子症和严重少精子症患者的细胞与分子遗传学特点。方法应用染色体核型分析、Y染色体微缺失检测和荧光原位杂交（FISH）、PCR等技术对非梗阻性无精子症（n=291）和严重少精子症患者（n=133）男性不育患者（共424例）进行细胞和分子遗传学检测。结果424例患者中有98例明确为遗传异常引起的,其中66例检测到染色体畸变,44例Y染色体微缺失检测见缺失,12例患者染色体核型和微缺失检测均见异常。部分AZF缺失患者精液或睾丸中有精子,但其生精功能呈进行性下降的特点。结论男性不育最常见的遗传学病因为K linefelter综合征和Y染色体AZFc缺失。Y染色体微缺失检测对Y染色体长臂异染色质区缺失是否为多态性具有明确诊断的作用。细胞与分子遗传学检测为男性不育的诊断、治疗和预后以及ICSI治疗前遗传咨询提供重要依据。     

Y染色体微缺失在无精子症及重度少弱精子症患者病因学研究中的应用

目的探讨Y染色体微缺失与无精症及重度少弱精症的关系。方法应用外周血染色体核型分析技术、多重聚合酶链反应技术及琼脂糖电泳技术,对300例无精症及重度少弱精患者进行外周血染色体核型分析、Y染色体微缺失基因检测。结果 300例患者共检测出染色体异常32例,Y染色体微缺失病例31例。结论 Y染色体微缺失为无精症和重度少弱精患者的重要病因,Y染色体微缺失检测对男科医生制定治疗方案具有重要指导意义。     

120例精子发生障碍的遗传缺陷研究

目的探讨无精子症,严重少精子症和少、弱精子症患者的遗传缺陷与男性不育的关系。方法采用外周血染色体核型分析技术和Y染色体基因微缺失检测方法,对120例无精子症,严重少精子症和少弱精子的患者进行了遗传咨询。结果在被筛查患者中发现异常染色体核型13例,异常核型发生率为10.83%;而其Y染色体微缺失检测中存在AZFc/SPGY基因缺失31例,缺失率25.83%。结论染色体核型异常和Y染色体微缺失与精子生成障碍有直接逻辑关系。Y染色体AZFc/SPGY区域的微缺失是中国男性不育的重要原因,因此,中国男性不育症患者有必要进行Y染色体AZFc/SPGY微缺失的常规筛查。     

无精子和少精子症患者Y染色体精子发生相关基因检测分析

目的探讨原因不明无精子症和少精子症患者与Y染色体精子发生相关基因的关系.方法对82例原因不明的无精子症和少精子症患者进行G带染色体核型分析,筛选核型正常无精子症和少精子症患者,采用多重PCR技术对Y染色体上AZF区15个序列标记位点进行检测.结果染色体核型异常16例,异常发生率为19.5%;66例核型正常无精子症和少精子症患者,有7例在Y染色体上出现不同位点基因片段微缺失,缺失率为10.6%.结论Y染色体上基因片段微缺失是造成无精子或少精子的重要原因之一,采用多重PCR技术对原因不明的无精子症和少精子症患者Y染色体精子发生相关基因进行检测分析是一种有效的好方法.     

150例无精子和少精子症患者Y染色体AZF区微缺失检测及染色体核型分析

目的分析无精子和少精子症患者Y染色体AZF基因微缺失与染色体核型的关联。方法对无精子、少精子症男性患者Y染色体AZF基因区15个STS位点进行检测和染色体核型分析。结果 150例患者经15个STS位点检测发现AZF区微缺失12例,总缺失率为8.0%。其中AZFa缺失2例,缺失频率为1.3%;AZFb缺失1例,缺失频率为0.6%;AZFc缺失11例,缺失频率为7.3%;AZFd缺失10例,缺失频率为6.7%。AZF区缺失频率为AZFc〉AZFd〉AZFa〉AZFb。12例AZF区微缺失的患者共存在4种缺失类型,其中10例患者为AZF区的联合缺失。所有患者经核型分析共检测出14例异常核型,异常率为9.3%。14例异常核型患者中有1例存在Y染色体微缺失;136例正常核型患者存在11例Y染色体微缺失。结论 Y染色体AZF区有缺失,不一定染色体核型异常,染色体核型异常也不排除有AZF的缺失;Y染色体微缺失与染色体核型异常不呈一一对应关系。     

男性不育的遗传病因研究

目的探讨染色体结构与数目异常,以及Y染色体无精子因子AZF微缺失和AZFc区部分缺失与男性不育的关系。方法运用多重PCR检测技术对494例无精子症、严重少精子症、少精子症患者和236例精液正常已生育男性进行AZF微缺失和AZFc部分缺失检测,并对494例男性不育患者进行外周血染色体核型分析。结果在无精子症、严重少精子症和少精子症患者中染色体数目与结构异常的发生率分别为11.86%(21/177)、3.39%(6/177)、2.08%(3/144)。无精子症和严重少精子症患者Y染色体AZF微缺失率明显高于少精子症组,差别有统计学意义(P0.05)。生精障碍组和严重少精子症组与正常对照组b2/b3缺失率差异均有统计学意义,而在各组间gr/gr缺失显示相似的频率。结论无精子症、严重少精子症和少精子症患者中存在较高频率的染色体结构、数目异常与AZF基因微缺失现象,提示染色体结构、数目异常与AZF基因微缺失可能是男性不育的重要遗传原因;Y染色体AZFc区存在多种部分缺失类型,gr/gr缺失可能对生精功能的影响较小,仅是一种基因组多态,b2/b3缺失是男性生精障碍的的风险因素。     

青岛地区69例无精子症和严重少精子症患者的遗传学分析

目的探讨无精子症和严重少精子症与遗传因素的关系。方法对69例无精子症和严重少精子症患者进行外周血染色体G显带核型分析,运用多重PCR技术检测Y染色体AZF基因家族AZFa、AZFb、AZFc三个区域中的6个序列标签位点(sequencet agged sites,STS)微缺失。结果 69例无精子症和严重少精子症患者中有染色体异常12例,Y染色体微缺失14例,其中有4例患者既存在染色体异常,又存在Y染色体微缺失。结论无精子症和严重少精子症与遗传缺陷密切相关。     

35例无精子症和严重少精子症患者的遗传学分析

目的探讨无精子症和严重少精子症与遗传因素的关系。方法35例无精子症和严重少精子症患者进行染色体G显带核型分析;运用多重PCR技术检测Y染色体AZF基因家族AZFa、AZFb、AZFc三个区域中的6个序列标签位点（sequence tagged sites,STS）微缺失。结果35例无精子症和严重少精子症患者中有13例发现遗传异常,其中染色体异常11例,Y染色体微缺失2例。结论无精子症和严重少精子症与遗传缺陷密切相关。     

柳州地区530例男性不育患者细胞遗传学与分子遗传学的分析

目的探讨Y染色体AZF基因缺失与男性不育症的关系,为临床辅助生殖技术提供理论支持。方法利用染色体核型分析、聚合酶链反应（polymerase chain reaction,PCR）和琼脂糖凝胶电泳（agarose gel electrophoresis,AGE）技术,对严重少弱精子症和无精子症男性不育患者进行无精子症因子（azoospermia factor,AZF）基因的15个位点分析。结果 530例不育症患者中有119例存在核型异常;34例存在AZF基因缺失,缺失率为6.4%。结论染色体数目结构异常与无精子症和严重少精子症的发生密切相关,Y染色体AZF基因缺失是导致男性不育的重要原因,辅助生殖治疗前有必要进行AZF基因缺失的检测。     

特发性无精子症和严重少精子症患者DAZ基因缺失的分析

目的　评估特发性无精子症和严重少精子症患者Y染色体上DAZ基因缺失的发生情况。方法　采用聚合酶链反应技术 (PCR)扩增 33例特发性无精子症和严重少精子症患者DAZ基因中的 4个序列标记位点SY15 4、SY2 5 4、SY2 5 5和SY15 5。 5 0例生育男性为阳性对照组 ,5例女性为阴性对照组。结果　 33例特发性无精子症和严重少精子症患者DAZ基因缺失率为 15 2 % ,其中 2 6例特发性无精子症患者有 4例缺失 (15 4 % ) ,1例染色体核型为 4 7,XXY ;7例特发性严重少精子症患者中有 1例缺失 (14 3% )。 4个序列标记位点在阳性对照组中均有条带扩增 ,在阴性对照组中未见条带扩增。结论　特发性无精子症和严重少精子症患者均存在DAZ基因缺失 ,特发性无精子症患者缺失率高于特发性严重少精子症患者 ,与国外报道相一致。聚合酶链反应扩增DAZ基因位点是筛选Y染色体缺失的有效方法。     

Transmission of a Y chromosomal deletion involving the deleted in azoospermia (DAZ) and chromodomain (CDY1) genes from father to son through intracytoplasmic sperm injection: case report.

The transmission of a deleted in azoospermia (DAZ) deletion from a severely oligozoospermic patient to his son following intracytoplasmic sperm injection (ICSI) treatment is reported. The case report highlights the fertilizing capacity of spermatozoa carrying Y chromosome deletions in patients treated with ICSI and stresses the importance of genetic counselling in severe male infertility.     

Absence of DAZ gene mutations in cases of non-obstructed azoospermia

Sequenced-tagged site (STS) analysis of the Y chromosome long arm (Yq) of azoospermic males has identified a minimum common deleted region of several hundred kilobases in approximately 13% of cases. A candidate azoospermia gene, DAZ (deleted in azoospermia), has been isolated from this region. DAZ has also been shown to be absent in severely oligozoospermic males albeit at a much lower frequency. These data, although highly suggestive, do not constitute formal proof that DAZ actually plays a role in azoospermia, as no small intragenic deletions, rearrangements or point mutations in the gene have been found. In this study we report the screening of DNA from 168 azoospermic/oligospermic males for the presence of the DAZ gene. Deletions involving DAZ were detected in five out of 43 (11.6%) azoospermic males whereas none were found in the remaining 125 oligospermic patients. We present the genomic structure of the 5' end of the DAZ gene together with its sequence analysis in 30 non-obstructed azoospermic males. No mutations in DAZ were found in any of the patients sequenced. These data provide no formal proof that DAZ is AZF. Thus the possibility is still valid that another gene(s) mapping to the deletion interval may be responsible for, or contribute to, the observed phenotypes. Alternatively, if DAZ is AZF, they suggest that the most frequent cause of gene inactivation is via large deletions possibly mobilized by Y chromosome repetitive sequences.      

Azoospermic men with deletion of the DAZ gene cluster are capable of completing spermatogenesis: fertilization, normal embryonic development and pregnancy occur when retrieved testicular spermatozoa are used for intracytoplasmic sperm injection

Some men with non-obstructive azoospermia harbour fully formed spermatozoa within their testicular tissue that can be used to achieve pregnancy via intracytoplasmic sperm injection (ICSI). Recently, Reijo et al. (1995) provided compelling evidence that the DAZ gene cluster is a strong candidate for one of the elusive azoospermia factors (AZF) located on the long arm of the Y chromosome. The DAZ gene cluster is deleted in 13% of azoospermic men and a small percentage of severely oligozoospermic men. Vertical transmission from father to son of AZF region deletions has also been described. Presumably these fathers were oligozoospermic. This led us to ask whether the azoospermic male with deletions of the AZF/DAZ region can also complete minimal spermatogenesis and whether any spermatozoa found could participate in fertilization, embryo development and pregnancy. Three out of six (50%) of the azoospermic men with AZF/DAZ deletions had spermatozoa identified within their harvested testicular tissue. When these spermatozoa were used for ICSI, fertilization occurred in 36% of injected oocytes. This compared favourably with testicular spermatozoa retrieved from non-obstructive azoospermic men without AZF/DAZ gene deletions. In one case, a twin conception resulted, which represents the first term pregnancy reported using spermatozoa from an AZF/DAZ deleted azoospermic male. Therefore it is necessary to take the possibility of transmission of infertility or sterility to our patients' offspring seriously when utilizing today's reproductive technologies, as spermatogenesis in men with AZF/DAZ deletions is by no means an exceptional occurrence.      

Y chromosome microdeletions, in azoospermic or near-azoospermic subjects, are located in the AZFc (DAZ) subregion

Submicroscopic deletions of the Y chromosome and polymorphisms of the androgen receptor (AR) gene in the X chromosome have been observed in men with defective spermatogenesis. To further define the subregions/genes in the Y chromosome causing male infertility and its relationship to polymorphisms of the AR polyglutamine tract, we screened the genomic DNA of 202 subfertile males and 101 healthy fertile controls of predominantly Chinese ethnic origin. Y microdeletions were examined with 16 sequence-tagged site (STS) probes, including the RBM and DAZ genes, spanning the AZFb and AZFc subregions of Yq11, and related to the size of trinucleotide repeat encoding the AR polyglutamine tract. Y microdeletions were detected and confirmed in three out of 44 (6.8%) of azoospermic and three out of 86 (3.5%) severely oligozoospermic patients. No deletions were detected in any of the patients with sperm counts of >0.5 x 10(6)/ml, nor in any of the 101 fertile controls. All six affected patients had almost contiguous Y microdeletions spanning the entire AZFc region including the DAZ gene. The AZFb region, containing the RBM1 gene, was intact in five of the six subjects. Y deletions were not found in those with long AR polyglutamine tracts. Our study, the first in a Chinese population, suggest a cause and effect relationship between Y microdeletions in the AZFc region (possibly DAZ), and azoospermia or near-azoospermia. Y microdeletions and long AR polyglutamine tracts appear to be independent contributors to male infertility.      

男性原发不育与DAZ基因家族部分拷贝缺失

目的　分析原发无精症和严重少精症患者 Y染色体无精症因子 C区 (azoospermia factor C,AZFc) DAZ基因 (deleted- in- azoospermia,DAZ)部分拷贝缺失的类型与频率。方法　 PCR扩增 DAZ基因区域的两个序列标签位点 (tag sequence site,STS) s Y5 81与 s Y5 87,用限制性片段长度多态性分析技术(restriction fragment length polymorphism,RFL P)检测 ,未发现 DAZ基因家族全部拷贝缺失的 197例原发无精症和 16 6例严重少精症患者实验组与 2 10名已正常生育男性对照组 ,进行 DAZ基因家族的部分拷贝缺失分析。结果　在实验组中发现 18例无精患者与 10例严重少精患者有 DAZ1/DAZ2共缺失 ,缺失率分别为 9.1%与 6 .0 % ,而对照组中未见部分基因拷贝缺失。实验组与对照组 DAZ1/DAZ2共缺失率差异有极显著性。结论　原发无精和严重少精症存在较高频率的 AZFc区 DAZ基因的部分缺失 ,这可能是中国男性原发不育的病因之一。中国人 AZFc区 DAZ1/DAZ2的共缺失及其缺失率与白人基本一致。应用PCR- RFL P进行 DAZ基因缺失分析可作为 AZF区域微缺失常规筛查后的补充。     

A putative human male infertility gene DAZLA: genomic structure and methylation status

The DAZLA (DAZ Like Autosomal) gene on human chromosome 3 shares a high degree of homology with the DAZ (Deleted in AZoospermia) gene family on the Y chromosome, a gene family frequently deleted in males with azoospermia or severe oligospermia. The involvement of both DAZ and DAZLA in spermatogenesis is suggested by their testis-specific expression and their homology with a Drosophila male infertility gene, boule. Whereas male infertility resulting from deletion of the DAZ genes on the Y chromosome occurs sporadically, that due to a defective DAZLA gene is expected to be inheritable. The fraction of males with idiopathic azoospermia or oligospermia that harbour mutations in the DAZLA gene remains unknown. As a prerequisite for mutation screening, the genomic structure of the DAZLA gene was elucidated and found to consist of 11 exons spanning 19 kh. The exon/intron boundaries are conserved between DAZ and DAZLA. The 5' end of both genes are hypomethylated in spermatozoa but not in leukocytes or placenta, consistent with the expression pattern of the genes. The genomic structure of DAZLA paves the way for mutation detection in families with autosomal recessive male infertility.      

Associations of Y-chromosome subdeletion gr/gr with the prevalence of Y-chromosome haplogroups in infertile patients

Microdeletions in azoospermia factor (AZF) region on distal Yq are associated with male infertility and spermatogenic failure due to intra-chromosomal homologous recombination between large nearly identical repeat amplicons and are found in ∼10% of azoospermic and severe oligozoospermic cases. Although AZFc is deleted in azoospermia or oligozoospermia, no definitive conclusion has been drawn for the role of partial AZFc deletions to spermatogenic failure. Therefore, this study is planned to investigate the role of gr/gr subdeletions in individuals with spermatogenic failure and to find its relationship with Y chromosome haplogroups (HGs) in infertile men from Indian population. It is a case-control study involving 236 azoospermic, 182 oligospermic and 240 healthy normozoospermic men. We found 18 gr/gr, 11 b1/b3 and 2 b2/b3 subdeletions in azoospermic patients and 12 gr/gr, 5 b1/b3 and 4 b2/b3 subdeletions in oligospermic patients. However, we also found seven gr/gr deletions in normozoospermic men. Seven patients each with spermatogenic arrest and oligospermia who carry gr/gr subdeletions have deleted DAZ3/DAZ4 genes. A total of 11 patients with sertoli cell-only syndrome (SCOS) and 5 oligospermic patients with gr/gr subdeletions also have DAZ1/DAZ2 genes deleted indicating that deletions of DAZ genes contributed differently to damage to spermatogenic process. L1 HG is found in patients showing b1/b3 subdeletions, whereas HG H1a2 and H1b were found in normozoospermic individuals with gr/gr subdeletions. Our results provide evidence of association between the occurrence of subdeletions and male infertility as well as the severity of the spermatogenic failure.     

The human autosomal gene DAZLA: testis specificity and a candidate for male infertility

The DAZ (Deleted in AZoospermia) and DAZLA (DAZ-like autosomal) genes may be determinants of male infertility. The DAZ gene on the long arm of the human Y chromosome is a strong candidate for the 'azoospermia factor' (AZF). Its role in spermatogenesis is supported by its exclusive expression in testis, its deletion in a high percentage of males with azoospermia or severe oligospermia, and its homology with a Drosophila male infertility gene boule. No DAZ homologous sequences have been found on the mouse Y chromosome. Instead, a Dazla gene was isolated from mouse chromosome 17 and has been considered to be a murine homologue of DAZ. However, the homology between human DAZ and mouse Dazla is not strong, and Dazla contains only one of the seven DAZ repeats found in DAZ. We report the isolation of the human DAZLA gene by screening a human testis cDNA library with a DAZ cDNA clone. DAZLA encodes only one DAZ repeat and shares high homology with the mouse Dazla, indicating that these two genes are homologues. Using a panel of rodent-human somatic cell lines and fluorescence in situ hybridization, the DAZLA gene was mapped to 3p24, a region not known to share homology with mouse chromosome 17. The DAZLA gene may be involved in some familial cases of autosomal recessive male infertility.      

Screening for microdeletions of Y chromosome genes in patients undergoing intracytoplasmic sperm injection.

The potential of assisted reproduction techniques to transmit genetic defects causing male infertility raises questions concerning the need for a systematic genetic screen and counselling. Deletions of the long arm of the Y chromosome are frequently associated with a failure of spermatogenesis. The search for Y specific sequences and for the gene families RNA binding motif (RBM) and deleted in azoospermia (DAZ) have been introduced in many laboratories. The incidence of Y microdeletions varies widely between studies, from 1-55%. These differences are mainly related to study design. The highest incidence of microdeletions has been reported in well selected idiopathic azoospermic patients. Since microdeletions have been reported also in non-idiopathic patients, it is important to define what is the deletion frequency in unselected patients. We report Y chromosome microdeletion screening in 134 unselected patients undergoing intracytoplasmic sperm injection (ICSI). In the first part of the study we tested six Y chromosome markers. We found three patients with microdeletions (2.2%). Subdivision of the study population revealed a deletion incidence of 4.7% in azoospermic/cryptozoospermic patients; an incidence of 7% in idiopathic patients and an incidence of 16% in idiopathic azoospermic/cryptozoospermic patients. The second part of the study consisted of a screen for the presence of the Y chromosome genes, DBY, CDY, XKRY, eIF-1A, DAZ and BPY2. No additional gene-specific deletions were found. Further data on gene specific screening are needed especially for selected idiopathic patients.