一例Y染色体长臂大片段缺失患者的缺失定位分析

目的 从分子遗传学角度对1例无精子症患者Y染色体无精子因子(azoospermia factor,AZF)区域缺失片段进行定位分析.方法 根据Y染色体遗传物理图谱,采用多重PCR技术扩增Y染色体AZFa区sY84、sY86、sY87,AZFb区sY102、sY117、sY118、sY119、sY115、DYS132、DYS385、sY1015、sY121、sY125、sY127、sY129、sY134,AZFd区sY152,AZFc区sY1258、sY1291、sY254、sY255、sY158、sY1201,Yq末端sY160等24个序列标签位点(sequence tag sites,SIS).结果 所扩增的SIS只有AZFa区sY84、sY86、sY87及AZFb区sY102、sY117、sY118、sY119、sY115、DYS132有特异扩增条带,其余15个STS均未见特异扩增条带.患者Y染色体缺失断裂点位于AZFb区sY115和DYS385之间约8577 bp范围内.为AZFb区部份缺失,AZFd区、AZFc区及Yq末端缺失.结论 用分子遗传学技术进行STS分析可精确标明Y染色体AZF区域缺失片段.     

Achievement of pregnancy in globozoospermia with Y chromosome microdeletion after ICSI

Pregnancy achieved with sperm from a patient with globozoospermia is rare, even after ICSI, since the activation of the oocyte may not occur in this disorder. Therefore, activation of the oocytes by piezoelectricity or calcium ionophores has been suggested, although spontaneous activation of the oocyte after ICSI has been reported in some cases. We report a successful pregnancy in a couple in which the male partner had globozoospermia with microdeletions in the Y chromosome with no further assisted activation after ICSI. During the diagnostic study of the husband, increased numerical chromosome abnormalities after fluorescent in-situ hybridization (FISH) and microdeletions in AZFa; sY86 and AZFb; sY 131 were detected. Out of the 13 oocytes injected, four fertilized and a twin pregnancy was obtained after replacement of four embryos. Healthy twin girls were delivered after a term pregnancy. Some patients with globozoospermia may also have Y chromosome microdeletions, which subsequently may be inherited by the male offspring in cases of achievement of pregnancy.     

对一例无精症患者Y染色体大片段缺失断裂位点的分析

目的 通过遗传物理图谱对Y染色体大片段缺失的断裂位点进行精确的定位，研究Y染色体无精子症因子（azoospennia factor，AZF）区域微缺失与无精症的关系。方法 应用多重PCR在4组反应管中对慨区的序列标签位点（sequence tagged site，SIS）即sY82，sY84，sY86，AZFb区的sY124，sY127，aY128，sY133，sY134，sY143，AZFc区的sY239，sY242，sY254，sY255和AZFd区的sY145，sY152共15个STS位点进行扩增，以性别决定因子为内控，根据多重PCR结果对sY82，sY86，sY85，sY84进行单独扩增。结果 对照组中的15个SIS位点及单独扩增的sY85中均有特异性扩增产物，而Y染色体异常患者样品仅有sY82，sY86扩增产物，其余呈阴性。从而将患者的近着丝粒端的断裂位点定位于sY86与sY85之间。结论 本研究为该患者的Y染色体大片段缺失断裂位点的精确定位提供了直接的分子生物学证据，建立了近着丝粒端的缺失图谱，证明了该患者无精的原因为AZF基因缺失。     

Klinefelter综合征患者Y染色体AZF微缺失分析

目的观察Klinefelter综合征患者Y染色体AZF微缺失发生情况。方法12例Klinefelter综合征患者ICSI/IVF等辅助受孕前进行睾丸细针穿刺吸液细胞学检查及Y染色体AZF微缺失分析。确定8个实验用序列标签位点（STS）,分别是：sY84、sY86、sY127、sY134、sY152、sY153、sY254、sY255,并以X/Y连锁锌指蛋白基因（ZFX/Y）为内对照进行多重PCR筛查AZF微缺失。结果睾丸细针穿刺吸液细胞学检查显示,3例（25.0%,3/12）可见到极少量形态较完整的精子及各级生精细胞、精子细胞,7例（58.3%,7/12）仅见少量生精细胞及精子细胞,2例（16.7%,2/12）仅见支持细胞,未见生精细胞及精子。12例Klinefelter综合征患者共检测出AZF微缺失2例分别为AZFa＋AZFc区缺失和AZFb＋AZFc区缺失;对照组32例样本未检出AZF基因微缺失。KS患者AZF微缺失检出率与对照组比较有显著差异（χ^2=5.587,P=0.018）。结论Klinefelter综合征患者存在Y染色体长臂AZF微缺失,缺失率为16.7%。     

Y染色体微缺失父子间垂直遗传分析

目的对Y染色体微缺失男性不育患者家系分析,探讨Y染色体微缺失父子间的自然垂直遗传。方法调查12例Y染色体无精子症因子(azoospermia factor,AZF)微缺失不育患者直系男性家族成员,取外周血抽提DNA进行改良多重PCR,绘制男子不育家系系谱图。结果12例家系中2例存在AZFc微缺失的家族遗传性。10例AZF微缺失患者仅本人存在缺失,没有家族遗传性。结论Y染色体AZFc微缺失有生育子代可能,并将这种微缺失自然垂直遗传给男性后代,且相同遗传类型可有不同的临床表型。     

Preliminary analysis of AZFb region duplication by quantitative real-time PCR

BACKGROUND: Deletions of the AZFb region on the long arm ofthe human Y chromosome cause male infertility. However, thereciprocal products of these deletion events, AZFb duplications,have not been reported to date. Furthermore, it is not knownwhether potential AZFb duplications represent a risk factorfor spermatogenic failure. METHODS: A total of 150 patientswith male idiopathic subfertility (79 non-obstructive azoospermicsand 71 oligozoospermics) and 150 fertile men were analysed fordeletion/duplication of the sY125 locus and of the JARID1D geneusing real-time PCR. RESULTS: Three azoospermic men had deletionof the sY125 locus and of the JARID1D gene. No duplication wasdetected. CONCLUSIONS: In our limited sample, AZFb duplicationsdo not appear to be associated with male infertility.     

中国人原发无精与严重少精症Y染色体AZF区域微缺失的分子流行病学研究

目的 明确与中国人原发无精和严重少精症密切相关的Y染色体无精症因子(azoospermia factor，AZF)区域微缺失位点及其缺失特点，为开展中国人AZF微缺失基因诊断提供理论依据。方法 采用多重聚合酶链反应技术，针对实验组134例原发无精、118例原发严重少精症患者与对照组210名已正常生育男性，进行AZFa、AZFb、AZFe三个区域共15个序列标签位点(sequence tag site，STS)的微缺失分析。结果 对照组在所有15个STS位点中均未发现缺失，实验组STS位点缺失涉及到13个STS位点，分别是：AZFa区的sY84、sY86，AZFb区的sYl21、sYl23、sYl24、sYl27、sYl34、sYl33，AZFc区的sYl52、sY242、sY254、sY255、sYl57。在5例无精患者中发现AZFa区STS位点缺失，缺失率为2．0％，在7例无精与3例少精患者中发现AZFb区STS位点缺失，缺失率为4．0％，在14例无精与18例少精患者中发现AZFc区STS位点缺失，缺失率为12．7％。统计学分析提示实验组与对照组13个STS位点缺失率差异有极显著性。结论所确定的AZF区域13个STS位点缺失与中国人原发无精和严重少精密切相关，未发现上述STS位点缺失的群体多态现象；中国人原发无精和严重少精症AZF区域微缺失的频率、分布、缺失热区与白人基本一致；所选择的13个STS位点可作为中国人原发无精与严重少精症AZF区域微缺失基因诊断筛查的候选位点。     

The human Y chromosome genes BPY2, CDY1 and DAZ are not essential for sustained fertility

Deletions of the AZFc interval of the human Y chromosome are found in >5% of male patients with idiopathic infertility and are associated with a severely reduced sperm count. The most common deletion type is large (>1 Mb) and removes members of the Y-borne testis-specific gene families of BPY2, CDY1, DAZ, PRY, RBMY2 and TTY2, which are candidate AZF genes. Four exceptional individuals who have transmitted a large AZFc deletion naturally to their infertile sons have, however, been described. In three cases, transmission was to an only son, but in the fourth case a Y chromosome, shown to be deleted for all copies of DAZ, was transmitted from a father to his four infertile sons. Here we present a second family of this latter type and demonstrate that an AZFc-deleted Y chromosome lacking not only DAZ, but also BPY2 and CDY1, has been transmitted from a father to his three infertile sons. Polymerase chain reaction (PCR) and Southern blot analyses revealed no difference in the size of the AZFc deletion in the father and his sons. We propose that the father carries rare alleles of autosomal or X-linked loci which suppress the infertility that is frequently associated with the absence of AZFc.     

Transmission of Y chromosomal microdeletions from father to son through intracytoplasmic sperm injection

 We conducted chromosomal analysis of three male infants fathered by severe oligozoospermic males with Y chromosomal microdeletions through intracytoplasmic sperm injection (ICSI). Two of the infants had the same Y chromosomal microdeletions as their fathers. The third infant also had a Y chromosomal microdeletion, which was longer than that found in his father. The results confirm that Y chromosomal microdeletions are transmitted from a father to a son via ICSI and also suggest that the microdeletions may be expanded during such transmission. Genetic counseling for infertile couples contemplating ICSI is important if the male carries Y chromosomal microdeletions. Received: January 11, 2002 / Accepted: May 19, 2002     

Prognostic value of Y deletion analysis: what is the clinical prognostic value of Y chromosome microdeletion analysis?

In many centres, Y chromosome deletion analysis is still not performed routinely and if so, the results are used for genetic counselling but are not considered as having a useful prognostic value. The type of deletion (AZFa, b or c) has been proposed as a potential prognostic factor for sperm retrieval in men undergoing TESE. AZFc deletions and partial AZFb deletions are associated with sperm retrieval in approximately 50% of cases while in the case of a patient with complete AZFb deletion the probability of finding mature spermatozoa is virtually nil. Therefore the extent and position of a Y microdeletion is important (complete or partial). The prognostic value of Y chromosome deletion analysis in cases of oligozoospermia is important when one considers the progressive decrease of sperm number over time in men with AZFc deletions. Cryo-conservation of spermatozoa in these cases could avoid invasive techniques, such as TESE/ICSI, in the future. Male offspring that are conceived by ICSI or IVF techniques from father with oligozoospermia or azoospermia would also benefit from knowledge of their Y status, since the identification of the genetic defect will render future medical or surgical therapies unnecessary. Y microdeletion screening is therefore important, not only to define the aetiology of spermatogenic failure, but also because it gives precious information for a more appropriate clinical management of both the infertile male and his future male child.     

The incidence and possible relevance of Y-linked microdeletions in babies born after intracytoplasmic sperm injection and their infertile fathers

Microdeletions linked to deletion intervals 5 and 6 of the Ychromosome have been associated with male factor infertility.Members from at least two gene families lie in the region containingazoospermia factor (AZF), namely YRRM and DAZ. With the adventof intracytoplasmic sperm injection (ICSI), it is possible formen with severe male factor infertility to produce a child.The genetic consequences of such a procedure have been questioned.This report describes the first study of a population (32 couples)of infertile fathers and their sons born after ICSI. The objectiveswere firstly to determine the incidence and map location ofY chromosome microdeletions and to compare the frequencies withother population studies involving severe male factor infertility,and secondly to formulate a working hypothesis concerning developmentalaetiology of Y chromosome microdeletions. The incidence of microdeletionsin the ICSI population was shown to be 9.4% (within the range9–18% reported for populations of severe male factor infertilitypatients). Microdeletions in two out of three affected fatherisonpairs mapped in the region between AZFb and AZFc and the thirdinvolved a large microdeletion in AZFb and AZFc. Of three affectedfather/son pairs, microdeletions were detected in the bloodof one infertile propositus father and three babies. Assumingthat the gonomes of the ICSI-derived babies are direct reflectionsof those of their fathers' germ lines, it is possible that twoof three infertile fathers were mosaic for intact Y and microdeletedY chromosomes. In such cases, the developmental aetiology ofthe microdeletion may be due to a de-novo microdeletion arisingas a post-zygotic mitotic error in the infertile propositusfather, thus producing a mosaic individual who may or may nottransmit the deletion to his ICSI-derived sons depending onthe extent of primordial germ cell mosaicism. In one of threeaffected fathers, the microdeletion detected in his blood wasalso detected in his ICSI-derived son. In this case the de-novoevent giving rise to the microdeletion may have occurred dueto a post- (or pre-) meiotic error in the germ line of thisfather's normally fertile father (i.e. the ICSI-derived baby'sgrandfather). aetiology/intracytoplasmic sperm injection/Y-chromosome microdeletions     

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.     

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.     

生殖激素水平在男性不育患者Y染色体微缺失中的研究

目的筛查严重少精子症和无精子症患者Y染色体AZF区域微缺失的发生情况,探讨Y染色体微缺失患者生殖激素的水平。方法对195例严重少精子症和80例无精子症患者进行Y染色体无精子因子（azoospermia factor,AZF）微缺失分析,同时用化学发光法测定生殖激素水平。结果275例患者中发生AZF微缺失患者21例,检出率为7．6％,其中少严重精子症15例,无精子症6例。21例AZF微缺失情况：AZFa区缺失3例;AZFb＋c＋d区缺失4例;AZFc＋d区缺失¨例;AZFd区缺失3例。Y染色体AZFb＋C＋d区缺失患者的卵泡刺激素（FSH）值（46．2±10．3）mIU／mL显著高于无Y染色体缺失患者（17．6±15．2）mIU／mL和AZFa区、AZFc＋d区、AZFd区缺失患者（15．8±5．7）mIU／mL,差异具有统计学意义（P〈0．05）。结论在无精与严重少精症患者中Y染色体的微缺失以AZFc区和AZFd区缺失最为常见,Y染色体AZFb＋c＋d区缺失是引起高卵泡刺激素的重要原因之一。     

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.     

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。     

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.     

Mitotic and meiotic behaviour of a naturally transmitted ring Y chromosome: reproductive risk evaluation

BACKGROUND: The mitotic and meiotic behaviour of a transmitted ring Y [r(Y)] chromosome from a father to his Klinefelter syndrome (KS) son, and the mechanism of ring formation are analysed herein. To our knowledge, this is the first reported case of natural transmission of an r(Y). METHODS AND RESULTS: Amplification of X chromosome polymorphisms by PCR showed that the KS was of paternal origin. G-banding and fluorescence in situ hybridization (FISH) studies revealed a similar percentage of mosaicism in father and son by mitotic loss of r(Y). SRY gene and Y marker amplification by PCR, FISH with subtelomeric probes for Xp/Yp and Xq/Yq, and comparative genomic hybridization (CGH) analyses indicated the intactness of the Y chromosome from SRY to subtelomere Yq. FISH analysis of sperm from the father showed significantly higher frequencies (P<0.005) for diploidy and for 6, 13, 18, 21, 22, XX, XY disomies than those observed in control donors. CONCLUSIONS: An r(Y) with low material loss can be naturally transmitted, showing similar mitotic behaviour in the offspring. The presence of an r(Y) chromosome in germinal cells increased the risk of fathering offspring with numerical abnormalities, even for chromosomes not involved in the arrangement.     

Molecular diagnosis of Y chromosome microdeletions in Europe: state-of-the-art and quality control

The polymerase chain reaction (PCR) screening of microdeletions of the Y chromosome has become an important diagnostic step in the work-up of male infertility. However, there is no agreement about how this diagnosis should be performed. There are suggestions that the large variation in deletion frequency reported in the literature could be due to the various selection criteria of the patients analysed, although methodological aspects may play a role as well. As for other genetic diseases, molecular diagnosis of Y chromosome microdeletions should be controlled by adopting strict internal quality control measures and by participating in external quality assessment schemes. Such an external quality assessment project is presently being organized jointly by the European Academy of Andrology and the European Molecular Genetics Quality Network. Three preliminary trials have given a state-of-the-art picture of the diagnostic performance in various European laboratories, showing an overall rate of misdiagnosis of approximately 5% for both AZFb and AZFc regions, and providing data useful in the generation of guidelines for the molecular diagnosis of Y chromosome microdeletions.