Y染色体小于22号染色体患者AZF微缺失分析

目的观察Y染色体≤22号染色体患者Y染色体微缺失的发生情况。方法本实验对象为47例Y染色体≤22号染色体患者,其中A组精子密度10×106/ml共12例,B组精子密度≥10×106/ml共35例,采用多重聚合酶链反应技术对其进行Y染色体微缺失15个序列标签位点进行检测。结果47例患者中共有4例发现微缺失,缺失率为8.51%;4例均为A组中发现,A组AZF总缺失率为33.33%,AZFa区缺失率为0%,AZFb区缺失率为25%,AZFc区及d区的缺失率均为33.33%,其中3例在无精子症中,缺失率为60%,1例在严重少精子症中,缺失率为14.29%;B组未发现微缺失,缺失率为0%。结论对于Y染色体≤22号染色体的男性,精子密度≥10×106/ml者AZF微缺失发生率很低;而无精子或严重少精子者,则有发生AZF微缺失的风险,尤其无精子症患者发生AZF多区域的联合缺失的风险显著增加。     

AZF微缺失与生精障碍症的研究分析

目的探讨Y染色体AZF微缺失与生精障碍症(男性原发性无精子症和少精子症)之间的关系。方法采用多重聚合酶链反应技术对158例生精障碍症患者(包括健康男性50例)进行AZFa、AZFb、AZFc和AZFd四个区域微缺失分析。结果 158例生精障碍症患者中发现AZF微缺失21例,总缺失率为13.3%。结论 Y染色体AZF区域微缺失与男性生精障碍症有着明显的相关性,因此有必要对生殖门诊及准备行辅助生育技术的生精障碍症患者行Y染色体AZF微缺失检测,其对该症的诊断及治疗具有重要的意义。     

180例无精子症或严重少精子症不育男性的Y染色体微缺失检测

目的探讨不育男性无精子症或严重少精子症与Y染色体微缺失之间的关系.方法利用9个Y染色体特异序列标签位点,以多重PCR法检测无精子症或严重少精子症患者的Y染色体微缺失情况.结果 180例无精子症或严重少精子症患者中共检出Y染色体微缺失15例,缺失率为8.3%.精液正常者(对照组)20例未发现Y染色体微缺失.9例Y染色体微缺失的无精子症患者睾丸细胞学检查均未发现精子.结论 Y染色体微缺失是造成男性精子发生障碍的常见病因之一.     

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。     

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。     

广州地区不育男性Y染色体无精子因子微缺失的筛查

目的探讨Y染色体无精子因子(azoospermia factor,AZF)区域微缺失与原发无精、严重少精症之间的关系。方法采用多重聚合酶链反应技术对广州地区103例原发无精子症、72例原发严重少精症患者及60名正常生育男性进行AZFa、AZFb、AZFc3个区域微缺失分析。结果60名正常生育男性未发现Y染色体AZF区域微缺失,175例生精障碍患者中发现AZF微缺失19例,总缺失率为10.9%。其中11例无精症患者和4例少精症患者的缺失发生在AZFc区域,缺失率为8.6%;1例无精症患者和2例少精症患者发生AZFb、AZFc双重缺失,缺失率为1.7%;1例无精症患者发生AZFa、b、c3个区域同时微缺失,缺失率0.6%。生精障碍组与正常生育男性组比较Y染色体AZF区域微缺失率差异具有统计学意义(P<0.01)。结论Y染色体AZF区域微缺失是引起男性无精、少精子症的重要原因之一,对原发无精、少精子症患者在单精子注射之前进行微缺失筛查是必要的。     

Interstitial and terminal deletion of chromosome Y in a male individual with cryptozoospermia

A constitutional de-novo deletion of the long arm of the Y chromosome was detected by standard cytogenetic analysis in a 38-year old male who, except for small testes and cryptozoospermia, was phenotypically normal. The deletion was further characterized by fluorescent in-situ hybridization (FISH) and digital image analysis using contigs of overlapping yeast artificial chromosome (YAC) clones, spanning almost the entire Y chromosome. These results showed that the deletion involved a large interstitial segment on the proximal long arm of the Y chromosome (Yq11.1-->Yq11.22) as well as a more distal portion of the Y chromosome, including the entire heterochromatic region (Yq11.23-- >qter). The breakpoints as determined by the YAC probes were defined within the published Vergnaud intervals so that region 6B and 6C was mostly retained. However, the AZFc region harbouring the DAZ locus on distal subinterval 6F was lost in the deletion, making the absence of this region the most probable location for the patient's infertility. The data underline the usefulness of FISH as an alternative technique to conventional banding for the refined detection of chromosome Y deletions/rearrangements.      

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.     

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.     

Sex chromosome mosaicism in males carrying Y chromosome long arm deletions

Microdeletions of the long arm of the Y chromosome (Yq) are a common cause of male infertility. Since large structural rearrangements of the Y chromosome are commonly associated with a 45,XO/46,XY chromosomal mosaicism, we studied whether submicroscopic Yq deletions could also be associated with the development of 45,XO cell lines. We studied blood samples from 14 infertile men carrying a Yq microdeletion as revealed by polymerase chain reaction (PCR). Patients were divided into two groups: group 1 (n = 6), in which karyotype analysis demonstrated a 45,X/46,XY mosaicism, and group 2 (n = 8) with apparently a normal 46,XY karyotype. 45,XO cells were identified by fluorescence in-situ hybridization (FISH) using X and Y centromeric probes. Lymphocytes from 11 fertile men were studied as controls. In addition, sperm cells were studied in three oligozoospermic patients in group 2. Our results showed that large and submicroscopic Yq deletions were associated with significantly increased percentages of 45,XO cells in lymphocytes and of sperm cells nullisomic for gonosomes, especially for the Y chromosome. Moreover, two isodicentric Y chromosomes, classified as normal by cytogenetic methods, were detected. Therefore, Yq microdeletions may be associated with Y chromosomal instability leading to the formation of 45,XO cell lines.     

男性少精子患者染色体和Y染色体微缺失检查

目的探讨男性少精子患者与外周血染色体异常及Y染色体微缺失的关系和临床意义。方法对150例男性少精子门诊患者同时进行外周血染色体核型分析和Y染色体微缺失检测。对照组为40例已正常生育的男性。结果150例男性少精子患者中,染色体异常30例,异常率20%;Y染色体微缺失8例,缺失率5.3%。对照组40例正常男性均未发现染色体异常和Y染色体微缺失。结论染色体异常或Y染色体微缺失是引起男性少精子的重要原因之一,对临床上少精子患者有必要进行染色体核型分析和Y染色体微缺失检测。     

25例无精症患者的分子细胞遗传学研究

目的 通过对无精症患者异常染色体及Y染色体(Yq11.2区段)无精症因子(azoospermic factor,AZF)微缺失的分析,探讨无精症与染色体异常的关系.方法 对25例原因不明的无精症患者进行G带染色体核型分析、荧光Q-显带、荧光原位杂交(fluorescence in situ hybridization,FISH)和AZF微缺失PCR检测.结果 25例原因不明的无精症患者中染色体核型异常7例,异常发生率为28%;对8例无精症患者进行AZF微缺失检测:AZF区微缺失2例,分别为AZFb(SYl27,SYl34)+AZFe(SY254,SY255)缺失、AZFe(SY243,sYl58)缺失.结论 染色体异常及Y染色体AZF微缺失是引起无精症并造成男性不育的重要原因之一,对无精症等不育男性患者在排除睾丸病变、阻塞性无精症、内分泌及免疫系统等临床病理学因素后,包括配偶有不明原因习惯性流产的男性均需做外周血染色体常规GTG-显带、荧光Q-显带检查.Q-带阴性的患者说明其Y染色体长臂缺失的断裂点高于Yq12,在Yq11.2区段,则需要结合FISH和AZF微缺失的PCR检测,以确诊Y染色体的微缺失区段,为患者的临床进一步治疗提供可靠的依据.     

Y染色体末端缺失患者的细胞遗传学及分子生物学分析

目的确定1例少弱精子患者G显带和C发现Yq末端缺失病例的核型,探讨YYq12缺失与表型关系。方法应用实验室常规染色体标本制备方法进行G显带和C显带,并应用Yq12区DYZ1探针和Yp11.1-q11.1区DYZ3探针与病例的中期分裂相进行荧光原位杂交(fluorescence in situ hybridization,FISH),同时应用PCR技术对患者进行了Y染色体微缺失的检测。结果G显带、C显带和FISH检测结果一致,均显示为Yq12区的缺失;Yq11区生精基因微缺失检测未发现该患者存在缺失。结论FISH结合细胞遗传学检测可以明确诊断染色体微小结构异常,Yq12区缺失可能是导致男性不育的原因之一。     

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。     

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.      

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.     

Analysis for microdeletions of Y chromosome in a single spermatozoon from a man with severe oligozoospermia

Since the association between Y chromosome deletions and spermatogenic failure was demonstrated in 1976, there have been many reports of Y chromosome microdeletions. Peripheral blood lymphocytes (PBLs) have been used for the analysis because the method is convenient, materials are easy to obtain, and PBL genomic DNA is similar to that of germ cells such as spermatozoa. However, PBLs originate from somatic tissue, not from germ cells. In this study, we analyzed 30 spermatozoa in semen ejaculated by an infertile male with Y chromosome microdeletions, while 50 spermatozoa from a normal fertile male were used as a control. The same Y chromosome microdeletion as that found in PBL was identified in each of the 12 spermatozoa which contained the Y chromosome in the infertile patient. These results indicated that spermatozoa (germ cells) had the same Y chromosome microdeletion as PBL (somatic cells). This supports the conjecture that microdeletions are transmitted to the next generation via the treatment of infertility by intracytoplasmic sperm injection. Received: October 17, 2000 / Accepted: November 15, 2000     

Patients with abnormal sperm parameters have an increased sex chromosome aneuploidy rate in peripheral leukocytes

BACKGROUND: Patients with oligoasthenoteratozoospermia (OAT) and normal karyotypes have an increased sperm aneuploidy rate. This may be due to an altered intratesticular environment that affects the chromosomal segregation mechanism(s). Alternatively, it may be due to a generalized meiotic and mitotic abnormality. In this case, patients with abnormal spermatogenesis should also have an increased somatic cell aneuploidy rate. To test this hypothesis, we evaluated peripheral leukocyte aneuploidy rate in patients with spermatogenic impairment. METHODS: In all, 38 patients were enrolled, of whom 20 had OAT, 15 non-obstructive azoospermia and three Y chromosome (Yq) microdeletions (AZF). Eight healthy normozoospermic men with proven fertility were recruited as controls. Conventional karyotype analysis, AZF microdeletion evaluation and triple-colour FISH for chromosomes X, Y and 12 were conducted in all patients and controls. A total of 1000 lymphocytes were scored for each patient and control. RESULTS: All patients and controls had a normal karyotype. Sex chromosome aneuploidy rates in peripheral lymphocytes was significantly higher in patients with OAT (0.74+/-0.09%), azoospermia (1.15+/-0.15%) or Yq microdeleted (1.54+/-0.40%), compared with controls (0.15+/-0.03%) (P <0.05). CONCLUSIONS: Patients with OAT, azoospermia or Yq microdeletions had a slight, but significant, increase of sex chromosome aneuploidy rate in lymphocytes, suggesting the presence of a generalized defective cell division mechanism. In contrast with recent observations, Yq microdeletions do not seem to predispose to a higher number of malsegregation events in somatic cells compared with patients with azoospermia.     

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。     

Clustering of Y chromosome deletions in subinterval E of interval 6 supports the existence of an oligozoospermia critical region outside the DAZ gene.

Y chromosome molecular analysis was performed using the STS-PCR technique in 50 patients with oligozoospermia. Microdeletions of interval 6 of the Y chromosome were detected in seven patients, in six of whom subinterval E was affected. All patients retained the RBM1 and DAZ genes, while in one deletion involved the SPGY gene. The size of the deletion was not apparently related to the severity of the disease. These results suggest the presence of an oligozoospermia critical region on the Y chromosome within subinterval E of interval 6.