Polymorphic DAZ gene family in polymorphic structure of AZFc locus: Artwork or functional for human spermatogenesis?

Human spermatogenesis is regulated by a network of genes located on autosomes and on sex chromosomes, but especially on the Y chromosome. Most results concerning the germ cell function of the Y genes were obtained by genomic breakpoint mapping studies of the Y chromosome of infertile patients. Although this approach has the benefit of focussing on those Y regions that contain most likely the Y genes of functional importance, its major drawback is the fact that fertile control samples were often missing. In fertile men, molecular and cytogenetic analyses of the Y chromosome has revealed highly polymorphic chromatin domains especially in the distal euchromatic part (Yq11.23) and in the heterochromatic part (Yq12) of the long arm. In sterile patients cytogenetic analyses mapped microscopically visible Y deletions and rearrangements in the same polymorphic Y regions. The presence of a Y chromosomal spermatogenesis locus was postulated to be located in Yq11.23 and designated as AZoospermia Factor (ZF). More recently, molecular deletion mapping in Yq11 has revealed a series of microdeletions that could be mapped to one of three different AZF loci: AZFa in proximal Yq11 (Yq11.21), AZFb and AZFc in two non-overlapping Y-regions in distal Yq11 (Yq11.23). This view was supported by the observation that AZFa and AZFb microdeletions were associated with a specific pathology in the patients' testis tissue. Only AZFc deletions were associated with a variable testicular pathology and in rare cases AZFc deletions were even found inherited from father to son. However, AZFc deletions were found with a frequency of 10-20% only in infertile men and most of them were proved to be "de novo", i.e. the AZFc deletion was restricted to the patient's Y chromosome. Based mainly on positional cloning experiments of testis cDNA clones and on the Y chromosomal sequence now published in GenBank, a first blueprint for the putative gene content of the AZFc locus can now be given and the gene location compared to the polymorphic DNA domains. This artwork of repetitive sequence blocks called AZFc amplicons raised the question whether the AZFc chromatin is still part of the heterochromatic domain of the Y long arm well known for its polymorphic extensions or is decondensed and part of the Yq11.23 euchromatin? We discuss also the polymorphic DAZ gene family and disclose putative origins of its molecular heterogeneity in fertile and infertile men recently identified by the analyses of Single Nucleotide Variants (SNVs) in this AZFc gene locus.     

特发性无精子症及少弱精子症患者Y染色体AZF微缺失筛查分析

目的探讨特发性无精子症及少弱精子症不育男性与Y染色体AZF微缺失的关系.方法用双重PCR技术对63例患者(无精于症41例,少弱精子症14例,严重少精子症8例)进行Y染色体AZFa、AZFb、AZFc、SRY的微缺失筛查.同时对26例无精于症患者行睾丸活检、组织学评估.结果63例中AZF微缺失7例,缺失率为11.1%.其中无精子症5例,严重少精子症2例.AZFc缺失4例,AZFb缺失2例,AZFb AZFc缺失1例,未发现AZFa区缺失.63例及对照组30例SRY基因扩增均阳性.26例无精子症患者行睾丸活检、组织学检查,无1例精子发生正常.结论Y染色体微缺失,特别是AZFc区DAZ基因的微缺失,是引起无精子和严重少弱精子等生精障碍而致男性不育较为重要的遗传学因素.     

COMMENTS

Human spermatogenesis is regulated by a network of genes located on autosomes and on sex chromosomes, but especially on the Y chromosome. Most results concerning the germ cell function of the Y genes were obtained by genomic breakpoint mapping studies of the Y chromosome of infertile patients. Although this approach has the benefit of focussing on those Y regions that contain most likely the Y genes of functional importance, its major drawback is the fact that fertile control samples were often missing. In fertile men, molecular and cytogenetic analyses of the Y chromosome has revealed highly polymorphic chromatin domains especially in the distal euchromatic part (Yq11.23) and in the heterochromatic part (Yq12) of the long arm. In sterile patients cytogenetic analyses mapped microscopically visible Y deletions and rearrangements in the same polymorphic Y regions. The presence of a Y chromosomal spermatogenesis locus was postulated to be located in Yq11.23 and designated as AZoospermia Factor (ZF). More recently, molecular deletion mapping in Yq11 has revealed a series of microdeletions that could be mapped to one of three different AZF loci: AZFa in proximal Yq11 (Yq11.21), AZFb and AZFc in two non‐overlapping Y‐regions in distal Yq11 (Yq11.23). This view was supported by the observation that AZFa and AZFb microdeletions were associated with a specific pathology in the patients' testis tissue. Only AZFc deletions were associated with a variable testicular pathology and in rare cases AZFc deletions were even found inherited from father to son. However, AZFc deletions were found with a frequency of 10–20% only in infertile men and most of them were proved to be “de novo”, i.e. the AZFc deletion was restricted to the patient's Y chromosome. Based mainly on positional cloning experiments of testis cDNA clones and on the Y chromosomal sequence now published in GenBank, a first blueprint for the putative gene content of the AZFc locus can now be given and the gene location compared to the polymorphic DNA domains. This artwork of repetitive sequence blocks called AZFc amplicons raised the question whether the AZFc chromatin is still part of the heterochromatic domain of the Y long arm well known for its polymorphic extensions or is decondensed and part of the Yq11.23 euchromatin? We discuss also the polymorphic DAZ gene family and disclose putative origins of its molecular heterogeneity in fertile and infertile men recently identified by the analyses of Single Nucleotide Variants (SNVs) in this AZFc gene locus.     

DAZ gene copies: evidence of Y chromosome evolution

The DAZ gene, a contributing factor in infertility, lies on the human Y chromosome's AZFc region, whose deletion is a common cause of spermatogenic failure. Y chromosome binary polymorphisms on the non-recombining Y (NRY) region, believed to be a single occurrence on an evolutionary scale, were typed in a sample of fertile and infertile men with known DAZ backgrounds. The Y single-nucleotide polymorphisms (Y-SNPs) with low mutation rates are currently well characterized and permit the construction of a unique phylogeny of haplogroups. DAZ haplotypes were defined using single-nucleotide variant (SNV)/sequence tagged-site (STS) markers to distinguish between the four copies of the gene. The variation of 10 Y chromosome short tandem repeat (STRs) was used to determine the coalescence age of DAZ haplotypes in a comparable time frame similar to that of SNP haplogroups. An association between DAZ haplotypes and Y chromosome haplogroups was found, and our data show that the DAZ gene is not under selective constraints and its evolution depends only on the mutation rate. The same variants were common to fertile and infertile men, although partial DAZ deletions occurred only in infertile men, suggesting that those should only be used as a tool for infertility diagnosis when analysed in combination with haplogroup determinations.     

Human male infertility and Y chromosome deletions: role of the AZF-candidate genes DAZ, RBM and DFFRY.

Microdeletions in Yq11 overlapping three distinct 'azoospermia factors' (AZFa-c) represent the aetiological factor of 10-15% of idiopathic azoospermia and severe oligozoospermia, with higher prevalence in more severe testiculopathies, such as Sertoli cell-only syndrome. Using a PCR-based screening, we analysed Yq microdeletions in 180 infertile patients affected by idiopathic Sertoli cell-only syndrome and different degrees of hypospermatogenesis, compared with 50 patients with known causes of testicular alteration, 30 with obstructive azoospermia, and 100 normal fertile men. In idiopathic severe testiculopathies (Sertoli cell-only syndrome and severe hypospermatogenesis), a high prevalence of microdeletions (34.5% and 24.7% respectively) was found, while milder forms were not associated with Yq alteration. No deletions were found in testiculopathies of known aetiology, obstructive azoospermia, normal fertile men and male relatives of patients with deletions. Deletions in the AZFc region involving the DAZ gene were the most frequent finding and they were more often observed in severe hypospermatogenesis than in Sertoli cell-only syndrome, suggesting that deletions of this region are not sufficient to cause complete loss of the spermatogenic line. Deletions in AZFb involving the RBM gene were less frequently detected and there was no correlation with testicular phenotype, with an apparent minor role for such gene in spermatogenesis. The DFFRY gene was absent in a fraction of patients, making it a candidate AZFa gene. Our data suggest that larger deletions involving more than one AZF-candidate gene are associated with a more severe testicular phenotype.     

Detection of sperm in men with Y chromosome microdeletions of the AZFa,AZFb and AZFc regions

BACKGROUND: Y chromosome microdeletions are associated with severe male factor infertility. In this study, the success rate of testicular sperm retrieval was determined for men with deletions of AZF regions a, b or c. METHODS: AZF deletions were detected by PCR of 30 sequence-tagged sites within Yq emphasizing the AZFa, b and c regions. Semen analysis and diagnostic testis biopsy or testicular sperm extraction (TESE) findings were correlated with the specific AZF region deleted. RESULTS: A total of 78 men with AZF deletions included three with AZFa deletion, 11 with AZFb, 42 with AZFc, 16 with AZFb+c and six with Yq (AZFa+b+c). All men with AZFa, AZFb, AZFb+c and Yq deletions were azoospermic and no sperm were found with TESE or biopsy. Of men with isolated AZFc deletion, sperm were found in 75% (9/12) by TESE and 45% (9/20) on biopsy (56% overall); 62% (26/42) were azoospermic and 38% (16/42) severely oligozoospermic. A total of 7 patients with deletion patterns that included the complete AZFa region and 23 that included the complete AZFb region who underwent TESE or biopsy did not have sperm detected by these surgical measures. CONCLUSIONS: Microdeletion of the entire AZFa or AZFb regions of the Y chromosome portends an exceptionally poor prognosis for sperm retrieval, whereas the majority of men with AZFc deletion have sperm within the semen or testes available for use in IVF/ICSI.     

无精和严重少精子症患者Y染色体的微缺失

目的 检测我国无精和严重少精子症患者Y染色体微缺失的发生情况和位点,及其与睾丸病理学类型的关系.方法 取584例无精子症和80例严重少精子症患者精液中细胞或外周血白细胞,裂解提取DNA,用4组多重聚合酶链反应检测分布于AZFa、AZFb、AZFc区,包括欧洲男科学会和欧洲分子遗传学质量控制体系推荐的6个位点在内的共15个序列标签位点(sequence tagged site,SIS)的缺失.对部分有Y染色体微缺失患者进行睾丸细针抽吸活检,检查睾丸病理学类型.结果 584例无精子症患者中,共有66例(11.3%)发生Y染色体微缺失,各区发生率构成比由高到低依次为:AZFc区48例(72.7%),AZFb+c区9例(13.6%),AZFa+b+c区4例(6.1%),AZFb区3例(4.5%),A2Fa区2例(3.0%).80例严重少精子症患者共有10例发生Y染色体微缺失(12.5%),均为AZFc区缺失.AZFc区缺失患者(19例)睾丸病理学类型多样化;AZFb+c区或AZFa+b+c区缺失患者(7例)睾丸病理学类型为唯支持细胞综合征或生精阻滞于精原细胞.结论 Y染色体微缺失在我国的发生情况与其他国家大多数报道基本一致,跨区大缺失对精子发生造成严重影响.     

Mice with Y chromosome deletion and reduced Rbm genes on a heterozygous Dazl1 null background mimic a human azoospermic factor phenotype

A subset of azoospermia or oligozoospermia patients have microdeletions in defined regions of their Y chromosome, namely the AZFa, b, and c regions. Candidate genes in humans that may cause the azoospermia factor (AZF) phenotype have been assigned to these regions and can include the DAZ and RBM genes. Part of the variability in the AZFc phenotype might be due to interaction between the effects of deleting the DAZ and RBM genes. We mimicked human deletions of RBM and DAZ in the mouse by crossing male mice with a deleted Y chromosome with a reduced number of Rbm genes (Y(d1)) to heterozygote Dazl1 null female mice to study the interaction of the Dazl1 and Rbm or other genes located in the Y(d1) deletion interval. Dazl-/+ Y(d1) animals showed a significant reduction in the sperm count (P < 0.001), an increase of abnormal sperm heads and prominent mid-piece defects of the tails compared to either mutation alone (P < 0.001). Hence, Dazl1 and the genes removed on the Y(d1) chromosome are active in different pathways contributing to different stages of spermatogenesis. Reduction of Dazl1 and Rbm genes as well as/or deletion of the Y chromosome in mice gives rise to a phenotype similar to the heterogeneous AZFc phenotype observed in humans.     

Analysis of Yq microdeletions in infertile males by PCR and DNA hybridization techniques

Defects in spermatogenesis have been found associated with deletions of different portions of Y chromosome long arm (Yq), suggesting the presence of the azoospermia factor in the control of spermatogenesis. We studied 67 men with idiopathic azoospermia and severe oligozoospermia, cytogenetically normal, for the presence of microdeletions on Yq chromosome. By using polymerase chain reaction (PCR) and Southern blotting techniques we analysed the AZFa, AZFb and AZFc loci on Yq, where deletions have been associated with defects in spermatogenesis. Deletions of a portion of the Y chromosome were detected in five patients. Four of these patients shared deletions in distal Yq11 interval 6, including the DAZ gene, while one patient lacked loci in the proximal Yq11. Testicular histology of two patients bearing distal Yq11 deletions showed two different spermatogenic defects including Sertoli cell-only (SCO) syndrome and maturation arrest, while the patient with microdeletions in the proximal Yq11 showed a SCO phenotype.      

AZF缺失患者Y染色体断裂点定位分析

目的 分析导致无精子因子区域(azoospermia factor,AZF)缺失的Y染色体断裂的特点.方法 在272例无精子症、240例严重少精子症患者进行Y染色体AZF微缺失筛查基础上,对筛查发现大片段缺失的49例患者,选择AZFa、AZFb、AZFc区23个序列标签位点(sequence tagged site,STS),对断裂点进行定位分析.颖有无精子症缺失基因家族(deletedin azoospermia,DAZ)、基因部分拷贝缺失病例进行单核苷酸多态性(single nuecleotide varians,SNV)缺失分析以确定DAZ基因的拷贝数.结果 6例AZFb+C缺失患者,1例为sY98/sY1206缺失,4例为P5/P1远端重组,1例为P4/P1远端重组.3例筛查发现AZFb区缺失患者,1例为P5/P3缺失,2例为P5/P1近端重组,伴有DAZ1、DAZ2拷贝缺失.40例AZFc区全缺失患者,均为b2/b4同源重组.部份AZFb、AZFb+c缺失患者,睾丸穿刺活检发现精子生成减少或精子成熟障碍.结论 对Y染色体AZF大片段缺失断裂点的大致定位有利于判断缺失发生机制,进而分析丢失的生精相关基因拷贝性质与数量,以评价其与生精障碍表型之间的关联.     

无精子和严重少精子患者Y染色体AZF微缺失的PCR筛查

目的：探讨Y染色体上AZF微缺失与精子生成的遗传效应关系,建立对无精子症和严重少精子患者Y染色体微缺失的筛查方法。方法;本文应用聚合酶链反应（PCR）技术对无精子症和严重少精子患者进行Y染色体上AZFa,AZFb,AZFc等5个基因片段的微缺失检测。结果：在64例无精子患者中,AZFb,AZFc,RBM人率分别为4．69％、17．19％、4．69％、未发现AZFa缺失。在53例严重少精子患者中,除1例同时伴有RBM缺失外,均为AZFc缺失,未发现AZFa和AZFb缺失,缺失率为18．87％。30例正常对照组未发现5个区域缺失。结论：精子发生与Y染色体上的多个基因有关,AZFb,AZFc的微缺失是导致无精子和严重少精子的重要原因,AZFc区微缺失可作病因筛查主要候选基因。     

Y chromosome microdeletions in Tunisian infertile males

AIM: To determine frequency of Y microdeletions in azoospermic and oligospermic Tunisian infertile males. METHODS: A Sample of 146 Tunisian infertile males with a low sperm count (<5 x 10(6) sperms per mililiter) and normal karyotype was screened for Y chromosome microdeletions. 76 men were azoospermic and 70 men were oligospermic. Genomic DNA was isolated from blood and multiplex PCR was carried out with a set of 20 AZFa, AZFb and AZFc STS markers to detect the microdeletions as recommended by the European Academy of Andrology. RESULTS: In 10/146 (6.85%) subjects AZF deletions were observed. Of these ten males with microdeletions, 9/10 subjects were azoospermic (90%), 1/10 was oligospermic (10%). Frequency of microdeletions in azoospermic men was 9/76 (11.84%). None of the patients showed isolated microdeletion in the AZFa region, but one azoospermic man had deletion in the AZFb region. Eight azoospermic patients and one oligospremic man have AZFc microdeletions. AZFc and AZFb were deleted in three azoospermic patients. AZFc, AZFb and AZFa were deleted in three azoospermic patients We estimate the sensitivity of the test comprising six STS in our sample to be 90%. CONCLUSION: The incidence of Yq microdeletions in the study population of infertile Tunisian men falls within the range published in other countries. We suggest to analyze 9STS in the first step to detect efficiently Y microdeletions in our population.     

618例不育男性的AZF基因微缺失分析

目的研究Y染色体AZF基因微缺失与男性不育的关系。方法应用多重PCR对618例男性不育患者进行Y染色体AZF基因的15个位点进行检测。结果一共检出Y染色体微缺失患者23例,占受检人群的3．72％,其中包括16例AZFc全部缺失、3例为AZFb＋c部分／全部缺失、3例为AZFa部分缺失和1例AZFa、AZFb、AZFc和AZFd四个区15个检测位点全部缺失。AZFc全部缺失患者中,中度至重度少精症13例,无精症3例;AZFb部分／全部缺失患者中,严重少弱精1例,无精症2例;AZFa部分缺失患者和15个位点全部缺失患者均为无精症。结论Y染色体AZF基因微缺失是男性不育的重要原因之一,该检测可为患者的诊断、治疗及遗传咨询提供依据。     

The prognostic role of the extent of Y microdeletion on spermatogenesis and maturity of Sertoli cells

Substantial involvement of the Y chromosome in sexual development and spermatogenesis has been demonstrated. Over the last decade, varying extent of Y chromosome microdeletions have been identified among infertile patients with azoospermia or oligozoospermia. These microdeletions were clustered in three main regions named AZFa, AZFb, and AZFc. Analysis of the Y chromosome microdeletion was found to be of prognostic value in cases of infertility, both in terms of clinical management as well as for understanding the aetiology of the spermatogenesis impairment. However, the accumulated data are difficult to analyse, due to the variable extent of these deletions, the different sequence-tagged sites (STS) used to detect the microdeletions, and the non-uniformity of the histological terminology used by different investigators. This debate discusses the chances of finding testicular spermatozoa in men with a varying extent of Y chromosome microdeletions. The genotype and germ cell findings in men with AZFa microdeletions as well as those that include more than a single AZF region are reviewed, as is the effect of Y chromosome AZF microdeletions on the maturity of the Sertoli cells.     

Microdeletions in the Y chromosome in cases of male infertility in a population of West Bengal

IntroductionInfertility is a burning problem in gynecological, andrological, endocrine and genetic practice. Of the myriad factors responsible for male infertility, which may be manifested as oligozoospermia or azoospermia, the exact causes of the latter are still unknown or debatable. Among the known parameters, the occurrence of microdeletions in the long arm of the Y chromosome are of great importance, as they have been consistently associated with defects in spermatogenesis. The microdeletions of the Y chromosome have been mapped to three regions in interval 6 named azoospermia factor regions (AZF), AZFa, AZFb and AZFc.MethodsIn the present study 80 males suffering from oligozoospermia or azoospermia were taken from both rural and urban infertility clinics and subjected to Polymerase Chain Reaction (PCR) of DNA from blood samples using a total of 11 STS primers. These primers correspond to different segments of the AZF regions (AZFa, AZFb and AZFc) and are known as Sequence Tagged Sites (STS). This was followed by agar gel electrophoresis to look for deletions in the AZF regions corresponding to the STF primers.ResultThese tests were able to detect microdeletions in the long arm of the Y chromosome in 4 patients.DiscussionIn majority of patients PCR detects no abnormality but in cases having microdeletions, appropriate advice could be given to the patients. These patients were told to avoid the use of their sperm in assisted reproduction procedures and accept the use of donor sperm or adoption procedures as a solution to their problems of infertility.     

男性不育患者Y染色体的AZF基因微缺失分析

目的探索男性不育患者Y染色体AZF基因微缺失的发生情况，为男性不育的临床诊断和治疗提供科学依据。方法应用PCR方法对36例无精或严重少精患者AZF基因的SY84、SY127和SY254进行检测分析。结果在36例患者中发现16例发生AZF基因的微缺失，均为三个基因区段不同组合的缺失。其中涉及AZFa或AZFb缺失的各8例，涉及AZFc缺失的有14例。结论AZF基因的微缺失与某些男性不育密切相关。AZFc缺失可能是男性不育中无精子、严重少精子的主要病因之一。     

不育男性的AZF检测与Y染色体缺失的对照分析

目的探讨精子发生障碍的男性不育患者AZF缺失与Y染色体缺失的临床意义。方法对616例非阻塞性无精子症或少精子症患者进行AZF的检测,同时观察G显带Y染色体的形态。结果从616例患者中检测出48例患者分别为AZFa、AZFb、AZFc或AZFb+AZFc的微缺失,但显微镜下观察不到Y染色体形态改变。另外4例患者经AZF检测,2例为AZFc+sY160缺失,1例为AZFb+AZFc+sY160缺失,1例为AZFa+AZFb+AZFc+sY160缺失,显微镜下发现Yq部分或完全缺失。25例已育男性的G-显带的Y染色体和AZF也进行对照检测,均未发现AZF的缺失,但其中1例核型分析显示Y染色体长臂部分缺失,但PCR检测仅缺失sY160,即Yq12的缺失。结论Yq11.23上7Mb的缺失在细胞水平不能分辨。q11.23+q12的缺失或仅有Yq12的缺失的Y染色体显微镜下不能区分,但后者不是精子发生障碍的病因。对男性不育精子发生障碍患者,要结合细胞遗传学和AZF分子检测综合判断。     

Lack of association between Y chromosome haplogroups and male infertility in Japanese men

The Y chromosome carries several genes involved in spermatogenesis, which are distributed in three regions in the euchromatic part of the long arm, called AZFa (azoospermia factor a), AZFb, and AZFc. Microdeletions in these regions have been seen in 10-15% of sterile males with azoospermia or severe oligozoospermia. The relatively high de novo occurrence of these microdeletion events might be due to particular chromosome arrangements associated with certain Y chromosome haplogroups. To test whether there is any association between Y chromosome types and male infertility, we studied a sample of 84 Japanese oligozoospermic or azoospermic males. The patients were analyzed for the presence of Yq microdeletions and also typed with a battery of unique event polymorphisms (UEPs) to define their Y haplogroups. Six of the infertile patients presented likely pathological microdeletions detectable with the sequence tagged sites (STS) markers used. There was no significant association between Y chromosome haplogroups and the microdeletions. We also compared the Y haplogroup frequencies in our subset sample of 51 idiopathic azoospermia patients with 57 fertile control Japanese males, and did not observe any significant differences. Contrary to previous reports, our data suggest that Y microdeletions and other molecular events causally associated with male infertility in Japan occur independently of the Y chromosome background.     

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.     

1000例无精子症和严重少精子症患者的Y染色体微缺失检测及分析

目的探讨Y染色体微缺失检测的意义。方法应用多重PCR对329例无精子症和671例严重少精子症患者行Y染色体AZFa、AZFb和AZFc基因微缺失检测。结果共检出Y染色体微缺失76例(7.6%),其中AZFc缺失60例(78.9%)。无精子症患者检出率为10%,严重少弱精子症患者检出率为6.4%,这两组缺失率有统计学意义(P0.05)。结论 AZFc缺失是最常见的缺失类型。无精子症患者Y微缺发生率较严重少精子症患者高。Y染色体微缺失检测为这类患者的遗传咨询提供重要依据。