Azoospermia Factor A Research Articles

Normal sperm quality despite partial deletion of sY84 in the AZFa region: A case report.

The complete absence of the azoospermia factor A (AZFa) region typically results in nonobstructive azoospermia. Partial deletions of the AZFa region are particularly noteworthy due to the limited and enigmatic reports of partial deletions in the AZFa region. Here, we present a rare case report of partial deletion of sY84 in the AZFa region but exhibiting normal sperm quality. The aim of this case report is to gain a deeper insight into the impact of AZFa region deletion on male fertility and to guide future clinical decisions and treatment strategies. A 25-year-old man presented to the hospital with his 25-year-old wife due to recurrent spontaneous abortions. Routine semen analysis, sperm morphology analysis, acrosomal enzyme analysis, sperm DNA fragmentation indexed, and peripheral blood karyotype analysis revealed no abnormalities. Y chromosome microdeletion was detected by real-time fluorescence polymerase chain reaction, which showed that sY84 could not be amplified and sY86 was amplified nonspecifically. The man was diagnosed with partial deletions in the AZFa region. The wife underwent in vitro fertilization treatment for tubal infertility and recurrent spontaneous abortions. The couple successfully delivered a healthy daughter weighing 2.7 kg at 39 weeks of gestation, following 2 assisted reproductive pregnancies. Our findings contribute to expanding our knowledge of the AZFa region. A sY84 deficiency in the AZFa region may not lead to spermatogenesis failure and may potentially be one of the factors causing recurrent miscarriages, which needs to be confirmed by further data.

Generate an AZFa deleted human embryonic stem cell line

Y chromosome deletion and karyotype abnormalities are commonly associated with congenital non-obstructive azoospermia, impairing spermatogenesis. Specifically, the deletion of the Y chromosome Azoospermia factor a (AZFa) has been identified in infertile males with severely impaired spermatogenesis. AZFa, encompassing megabase-scale of the Y chromosome region, poses challenges in modeling AZFa deletion-related male infertility using gene editing tools. Here, we successfully created an AZFa-deleted human embryonic stem cell line utilizing the CRISPR/Cas9 gene editing tool. Our analysis indicates the AZFa-deleted stem cell line holds promise for differentiation into ectoderm, mesoderm, and endoderm, highlighting its potential for further comprehensive study.

Whole-exome sequencing in patients with maturation arrest: a potential additional diagnostic tool for prevention of recurrent negative testicular sperm extraction outcomes.

STUDY QUESTIONCould whole-exome sequencing (WES) be useful in clinical practice for men with maturation arrest (MA) after a first testicular sperm extraction (TESE)?SUMMARY ANSWERWES in combination with TESE yields substantial additional information and may potentially be added as a test to predict a negative outcome of a recurrent TESE in patients with MA.WHAT IS KNOWN ALREADYAt present, the only definitive contraindications for TESE in men with non-obstructive azoospermia (NOA) are a 46,XX karyotype and microdeletions in the azoospermia factor a (AZFa) and/or AZFb regions. After a first negative TESE with MA, no test currently exists to predict a negative outcome of a recurrent TESE.STUDY DESIGN, SIZE, DURATIONIn a cohort study, we retrospectively included 26 patients with idiopathic NOA caused by complete MA diagnosed after a first TESE.PARTICIPANTS/MATERIALS, SETTING, METHODSTwenty-six men with MA at the spermatocyte stage in all seminiferous tubules, according to a histopathological analysis performed independently by two expert histologists, and a normal karyotype (i.e. no AZF gene microdeletions on the Y chromosome) were included. Single-nucleotide polymorphism comparative genomic hybridization array and WES were carried out. The results were validated with Sanger sequencing. For all the variants thought to influence spermatogenesis, we used immunohistochemical techniques to analyse the level of the altered protein.MAIN RESULTS AND THE ROLE OF CHANCEDeleterious homozygous variants were identified in all seven consanguineous patients and in three of the 19 non-consanguineous patients. Compound heterozygous variants were identified in another 5 of the 19 non-consanguineous patients. No recurrent variants were identified. We found new variants in genes known to be involved in azoospermia or MA [including testis expressed 11 (TEX11), meiotic double-stranded break formation protein 1 (MEI1), proteasome 26s subunit, ATPase 3 interacting protein (PSMC3IP), synaptonemal complex central element protein 1 (SYCE1) and Fanconi anaemia complementation group M (FANCM) and variants in genes not previously linked to human MA (including CCCTC-binding factor like (CTCFL), Mov10 like RISC complex RNA helicase 1 (MOV10L1), chromosome 11 open reading frame 80 (C11ORF80) and exonuclease 1 (EXO1)].LARGE SCALE DATAData available on requestLIMITATIONS, REASONS FOR CAUTIONMore data are required before WES screening can be used to avoid recurrent TESE, although screening should be recommended for men with a consanguineous family background. WES is still a complex technology and can generate incidental findings.WIDER IMPLICATIONS OF THE FINDINGSOur results confirmed the genetic aetiology of MA in most patients: the proportion of individuals with at least one pathologic variant was 50% in the overall study population and 100% in the consanguineous patients. With the exception of MEI1 (compound heterozygous variants of which were identified in two cases), each variant corresponded to a specific gene—confirming the high degree of genetic heterogeneity in men with MA. Our results suggest that WES screening could help to avoid recurrent, futile TESE in men with MA in general and in consanguineous individuals in particular, but these results need to be confirmed in future studies before clinical implementation.STUDY FUNDING/COMPETING INTEREST(S)The study was funded by the Fondation Maladies Rares (Paris, France), Merck (Kenilworth, NJ, USA), IRSF (Montigny le Bretonneux, France) and Agence de la Biomédecine (Saint Denis, France). There are no competing interests.TRIAL REGISTRATION NUMBERN/A.

Detection of partial and/or complete Y chromosome microdeletions of azoospermia factor a (AZFa) sub-region in infertile Iraqi patients with azoospermia and severe oligozoospermia.

BackgroundThis study aimed to analyze the incidence of azoospermia factor a (AZFa) microdeletions in the Y chromosome and their association with male infertility in a population with azoospermia and severe oligozoospermia from Iraq.MethodsA total of 75 infertile Iraqi males and 25 healthy controls were included in this study. The semen analysis was performed to determine the azoospermia, severe oligozoospermia, or normal cases. The AZFa microdeletions were investigated using the real‐time polymerase chain reaction (real‐time PCR). Then, AZFa sub‐region deletions were investigated by a conventional PCR.ResultsIn total, 40 men with azoospermia and 35 men with severe oligozoospermia were selected. Out of 75 infertile males, 46 (61.3%) individuals had AZFa microdeletions, of whom 32 (69.6%) had partial deletion, while 14 (30.4%) males had complete deletion using real‐time PCR. The frequency of microdeletions was significantly different between the infertile and control group (p‐value < 0.00001). The proportion of AZFa microdeletions appeared higher in azoospermia men (72.5%, n = 29/40) than severe oligozoospermia men (48.6%, n = 17/35), but based on the conventional PCR results, only one azoospermia patient (2.2%) was shown to have complete AZFa deletion, while the other 45 patients (97.8%) had partial AZFa deletions.ConclusionIn this study, the partial AZFa microdeletions were more numerous than complete AZFa deletion. According to our results, the AZFa microdeletions might be associated with male infertility and spermatogenic failure. It is recommended to investigate the AZFa sub‐region microdeletions in patients that shown AZFa microdeletions in primary screening.

AZFa candidate gene UTY and its X homologue UTX are expressed in human germ cells.

SummaryThe Ubiquitous Transcribed Y (UTY a.k.a. KDM6C) AZFa candidate gene on the human Y chromosome and its paralog on the X chromosome, UTX (a.k.a. KDM6A), encode a histone lysine demethylase removing chromatin H3K27 methylation marks at genes transcriptional start sites for activation. Both proteins harbour the conserved Jumonji C (JmjC) domain, functional in chromatin metabolism, and an extended N-terminal tetratricopeptide repeat (TPR) block involved in specific protein interactions. Specific antisera for human UTY and UTX proteins were developed to distinguish the expression of both proteins in human germ cells by immunohistochemical experiments on appropriate tissue sections. In the male germ line, UTY was expressed in the fraction of A spermatogonia located at the basal membrane, probably including spermatogonia stem cells. UTX expression was more spread in all spermatogonia and in early spermatids. In female germ line, UTX expression was found in the primordial germ cells of the ovary. UTY was also expressed during fetal male germ cell development, whereas UTX expression was visible only at distinct gestation weeks. Based on these results and the conserved neighboured location of UTY and DDX3Y in Yq11 found in mammals of distinct lineages, we conclude that UTY, such as DDX3Y, is part of the Azoospermia factor a (AZFa) locus functioning in human spermatogonia to support the balance of their proliferation-differentiation rate before meiosis. Comparable UTY and DDX3Y expression was also found in gonadoblastoma and dysgerminoma cells found in germ cell nests of the dysgenetic gonads of individuals with disorders of sexual development and a Y chromosome in karyotype (DSD-XY). This confirms that AZFa overlaps with GBY, the Gonadoblastoma susceptibility Y locus, and includes the UTY gene.Lay summaryAZFa Y genes are involved in human male germ cells development and support gonadoblastoma (germ cell tumour precursor cells) in the aberrant germ cells of the gonads of females with genetic disorders of sexual development. The AZFa UTY gene on the male Y chromosome is equivalent to UTX on the female X chromosome. These genes are involved in removing gene regulators to enable activation of other genes (i.e. removal of histone methylation known as epigenetic modifications). We wanted to learn the function of UTY and UTX in developing sperm and eggs in human tissues and developed specific antibodies to detect both proteins made by these genes. Both UTY and UTX proteins were detected in adult and fetal sperm precursor cells (spermatogonia). UTX was detected in egg precursor cells (primordial germ cells). UTY was detected in gonadoblastoma and dysgerminoma tumour cells (germ cell tumours originating from genetic disorders of sexual development due to having a Y chromosome). Based on our study, we conclude that UTY is not only part of AZFa, but also of GBY the overlapping gonadoblastoma susceptibility Y region.

An azoospermic factor gene, Ddx3y and its paralog, Ddx3x are dispensable in germ cells for male fertility.

About 10% of male infertile patients show abnormalities in spermatogenesis. The microdeletion of azoospermia factor a (AZFa) region of the Y chromosome is thought to be a cause of spermatogenic failure. However, candidate gene responsible for the spermatogenic failure in AZFa deleted patients has not been elucidated yet. Using mice, we explored the function of Ddx3y, a strong candidate gene in the Azfa region, and Ddx3x, a Ddx3y paralog on the X chromosome, in spermatogenesis. We first generated Ddx3y KO male mice using CRISPR/Cas9 and found that the Ddx3y KO male mice show normal spermatogenesis, produce morphologically normal spermatozoa, and sire healthy offspring. Because Ddx3x KO males were embryonic lethal, we next generated chimeric mice, which contain Ddx3x and Ddx3y double KO (dKO) germ cells, and found that the dKO germ cells can differentiate into spermatozoa and transmit their mutant alleles to offspring by normal mating. We conclude that Ddx3x and Ddx3y are dispensable for spermatogenesis at least in mice. Unlike human, mice have an additional Ddx3y paralog D1pas1, that has been reported to be essential for spermatogenesis. These findings suggest that human and mouse DDX3 related proteins have distinct differences in their functions.

208 - Clinical and Biological Significance of Y Chromosome Loss in a Series of 2,423 Male Patients with MDS and CMML

Yq microdeletion is one of the well-known genetic causes of infertility in males which results in spermatogenetic impairment. Among the three regions (AZFa, AZFb and AZFc), deletion in Azoospermia Factor a (AZFa) sub-region of the human Y-chromosome considered to have most severe outcome and may cause spermatogenic failure where Sertoli-Cell Only (SCO) syndrome occur in clinically tested testis. Because of the deletion, men may not form or able to keep up the nascent germ cells cohort during adolescence and after that. The AZFa sub-region contains mainly three candidate genes, USP9Y (Ubiquitin specific peptidase 9, Y-linked), DBY (DEAD/H Box 3, Y-linked) and UTY (Ubiquitously Transcribed Tetratricopeptide Repeat Containing, Y-Linked) whose defined role are unknown. This review article makes understand about the deletion mechanism and all the three genes of AZFa sub-region related to infertility in men.

Progress in understanding the molecular functions of DDX3Y (DBY) in male germ cell development and maintenance.

Human DDX3 paralogs are housed on the X chromosome (DDX3X) as well as in the non- recombining region Yq11 of the Y-chromosome (DDX3Y or DBY). A gene encoding RNA helicase DDX3Y is located in the AZoospermia Factor a (AZFa) region of the Y-chromosome and expressed only in male germ cells. Deletions encompassing the DDX3Y gene lead to azoospermia and cause Sertoli Cell-Only Syndrome (SCOS) in humans. SCOS is characterized by a complete germ cell lack with preservation of somatic Sertoli cells. This review summarizes current advances in the study of DDX3Y functions in maintenance and development of early male germ cells. Data obtained from a mouse xenotransplantation model reveals that DDX3Y expression is enough to drive germ cell differentiation of AZFa-deleted human induced pluripotent stem cells (iPSCs) and for activation of the specific set of germline developmental genes. Results achieved using the testes of Drosophila demonstrate that DDX3Y homolog Belle is required cell-autonomously for mitotic progression and survival of germline stem cells and spermatogonia as the upstream regulator of mitotic cyclin expression.

Salvage hormonal therapy after failed microdissection testicular sperm extraction: A multi-institutional prospective study.

To validate the efficacy of salvage hormonal therapy in men with non-obstructive azoospermia at their second microdissection testicular sperm extraction. This was a multi-institutional study registered at the Japanese University Hospital Medical Information Network clinical trial center. After 1month of human chorionic gonadotropin therapy (5000IU, three times a week), patients were treated with recombinant human follicle-stimulating hormone (150IU, three times a week) and human chorionic gonadotropin for the next 3months. Three testicular samples were obtained randomly from both testes, and sent for pathological diagnosis at the first and second microdissection testicular sperm extraction. A total of 21 men, excluding those with chromosomal abnormalities, azoospermia factora or b deletions, extremely small testes (<2mL), or prior hormonal therapy, were eligible to participate based on our inclusion criteria. At the first microdissection testicular sperm extraction, 13 and six patients had Sertoli cells only and an early maturation arrest, respectively. With the second microdissection testicular sperm extraction, sperm were successfully obtained from two patients (10%). Patient age, testicular volume and hormone profiles were not associated with the results of the second microdissection testicular sperm extraction. However, the testicular histology of the two successful patients were late maturation arrest and hypospermatogenesis. Effectiveness of human chorionic gonadotropin-based salvage hormonal therapy preceding a second microdissection testicular sperm extraction seems to be limited. Non-obstructive azoospermia men who have differentiated cells in their testes are likely to respond to hormonal stimulation.

DDX3Y gene rescue of a Y chromosome AZFa deletion restores germ cell formation and transcriptional programs.

Deletions of the AZFa region (AZoospermia Factor-a) region of the human Y chromosome cause irreversible spermatogenic failure that presents clinically in men as Sertoli-cell only (SCO) pathology of the testis. Deletions of the AZFa region typically encompass two genes: DDX3Y and USP9Y. However, human genetic evidence indicates that SCO is most tightly linked to deletion of DDX3Y and that deletions/mutations of USP9Y can be transmitted from one generation to the next. Here, we generated stable iPSC lines with AZFa deletions, tested complementation via introduction of DDX3Y, and assessed ability to form germ cells in vivo in a xenotransplantation model. We observed a quantifiable improvement in formation of germ cell like cells (GCLCs) from complemented donor iPSCs. Moreover, expression of UTF1, a prospermatogonial protein, was restored in cells complemented by introduction of DDX3Y on the AZFa background. Whole-genome RNA sequencing of purified GCLCs revealed an enrichment of genes involved in translational suppression and transcriptional control in DDX3Y-rescued GCLCs over mutant GCLCs, which maintained a molecular phenotype more similar to undifferentiated iPSCs. This study demonstrates the ability to probe fundamental genetics of human germ cell formation by complementation and indicates that DDX3Y functions in the earliest stages of human germ cell development.

GREAM: A Web Server to Short-List Potentially Important Genomic Repeat Elements Based on Over-/Under-Representation in Specific Chromosomal Locations, Such as the Gene Neighborhoods, within or across 17 Mammalian Species.

BackgroundGenome-wide repeat sequences, such as LINEs, SINEs and LTRs share a considerable part of the mammalian nuclear genomes. These repeat elements seem to be important for multiple functions including the regulation of transcription initiation, alternative splicing and DNA methylation. But it is not possible to study all repeats and, hence, it would help to short-list before exploring their potential functional significance via experimental studies and/or detailed in silico analyses.ResultWe developed the ‘Genomic Repeat Element Analyzer for Mammals’ (GREAM) for analysis, screening and selection of potentially important mammalian genomic repeats. This web-server offers many novel utilities. For example, this is the only tool that can reveal a categorized list of specific types of transposons, retro-transposons and other genome-wide repetitive elements that are statistically over-/under-represented in regions around a set of genes, such as those expressed differentially in a disease condition. The output displays the position and frequency of identified elements within the specified regions. In addition, GREAM offers two other types of analyses of genomic repeat sequences: a) enrichment within chromosomal region(s) of interest, and b) comparative distribution across the neighborhood of orthologous genes. GREAM successfully short-listed a repeat element (MER20) known to contain functional motifs. In other case studies, we could use GREAM to short-list repetitive elements in the azoospermia factor a (AZFa) region of the human Y chromosome and those around the genes associated with rat liver injury. GREAM could also identify five over-represented repeats around some of the human and mouse transcription factor coding genes that had conserved expression patterns across the two species.ConclusionGREAM has been developed to provide an impetus to research on the role of repetitive sequences in mammalian genomes by offering easy selection of more interesting repeats in various contexts/regions. GREAM is freely available at http://resource.ibab.ac.in/GREAM/.

Success rate of microsurgical multiple testicular sperm extraction and sperm presence in the ejaculate in korean men with y chromosome microdeletions.

PurposeWe assessed the frequency of azoospermia factor a (AZFa), AZFb, and AZFc deletions and examined correlations between the deletion sites and the success rates of sperm presence within the ejaculate and surgical sperm retrieval in Korean men.Materials and MethodsA total of 1,919 azoospermic and severely oligozoospermic men were assessed for Y chromosome microdeletions. Among them, 168 men with AZF deletions were identified and their medical records were reviewed.ResultsOf the total 168 men with AZF deletions, there were 13 with AZFa, 10 with AZFb, 95 with AZFc, 37 with AZFbc, and 13 with AZFabc deletions. Of the 95 men with isolated AZFc deletion, 51 had the presence of sperm in the ejaculate. Of the infertile men with any other deletion, however, only two patients (one man with AZFb deletion and another with AZFbc deletion) showed the presence of sperm in the ejaculate. The success rates for surgical sperm retrieval were 7.1% (1/14) in men with AZFbc deletion and 54.8% (17/31) in the isolated AZFc deletion group. No sperm was obtained from the patients with AZFa or AZFb deletions who underwent microsurgical sperm retrieval. In the isolated AZFc deletion group, there were significant differences between azoospermic and severely oligozoospermic patients in terms of testicular volume and serum levels of follicle-stimulating hormone and luteinizing hormone, whereas no significant differences were found when the group was divided by surgical sperm retrieval outcomes.ConclusionsDeletions of the AZFa and AZFb regions are associated with severe spermatogenetic impairment. However, more than half of men with an AZFc deletion had sperm within the ejaculate or testis for in vitro fertilization with intracytoplasmic sperm injection.

AZFa protein DDX3Y is differentially expressed in human male germ cells during development and in testicular tumours: new evidence for phenotypic plasticity of germ cells

DDX3Y (DBY), located within AZoospermia Factor a (AZFa) region of the human Y chromosome (Yq11), encodes a conserved DEAD-box RNA helicase expressed only in germ cells and with a putative function at G1-S phase of the cell cycle. Deletion of AZFa results most often in germ cell aplasia, i.e. Sertoli-cell-only syndrome. To investigate the function of DDX3Y during human spermatogenesis, we examined its expression during development and maturation of the testis and in several types of testicular germ cell tumours (TGCTs), including the pre-invasive carcinoma in situ (CIS) precursor cells which are believed to originate from fetal gonocytes. DDX3Y protein expression was analysed during development in different tissues by western blotting. The localization of DDX3Y in normal fetal and prepubertal testis tissue of different ages as well as in a series of distinct TGCT tissue samples (CIS, classical seminoma, spermatocytic seminoma, teratoma and embryonal carcinoma) was performed by immunohistochemistry. Germ cell-specific expression of DDX3Y protein was revealed in fetal prospermatogonia but not in gonocytes and not before the 17th gestational week. After birth, DDX3Y was expressed at first only in the nuclei of Ap spermatogonia, then also in the cytoplasm similarly to that seen after puberty. In CIS cells, DDX3Y was highly expressed and located predominantly in the nuclei. In invasive TGCT, significant DDX3Y expression was found in seminomas of the classical and spermatocytic type, but not in somatically differentiated non-seminomas, consistent with its germ-cell specific function. The fetal germ cell DDX3Y expression suggests a role in early spermatogonial proliferation and implies that, in men with AZFa deletion, germ cell depletion may begin prenatally. The strong expression of DDX3Y in CIS cells, but not in gonocytes, indicates phenotypic plasticity of CIS cells and suggests partial maturation to spermatogonia, likely due to their postpubertal microenvironment.

Prevalent false positives of azoospermia factor a (AZFa) microdeletions caused by single-nucleotide polymorphism rs72609647 in the sY84 screening of male infertility

Multiplex polymerase chain reaction (PCR) has been widely used to detect Y-chromosome microdeletions, which is one of the major causes of male infertility. Both the European Academy of Andrology (EAA) and the European Molecular Genetics Quality Network (EMQN) have recommended the use of sY84 and sY86 markers for the detection of azoospermia factor a (AZFa) microdeletion during DNA testing for male infertility. In this study, a large-scale analysis of AZF microdeletion in a total of 630 Chinese males, including healthy semen donors (n=200), infertile males with normal sperm count (n=226) and patients with either nonobstructive azoospermia or severe oligozoospermia (n=204), was performed. A series of nine sequence-tagged site (STS) markers from the AZF region of the Y chromosome was used to detect microdeletions. All primers were designed based on the recommendations of the National Center for Biotechnology Information. An unusually high incidence (73/630, 11.6%) of sY84-absent but sY86-present genotypes was observed in the AZFa microdeletion screening. Sequencing the sY84-flanking region revealed a total of 73 patients with sY84-absent but sY86-present genotypes have a T-to-G transversion at the fifth base from the 5' end of the reverse sY84 primer. These prevalent false positives, which were not only observed in infertile men, but also observed in donors, resulted from a single-nucleotide polymorphism (SNP) named rs72609647 in the targeting sequence of the reverse sY84 primer. Our study suggests that a pre-screening of existence of rs72609647 polymorphism can prevent the frequent false positive results of AZFa microdeletions detection in the infertile Chinese males. Given the SNP rs72609647 was recently found in a deep sequencing of a Chinese individual, the current EAA and EMQN standards may need to be scrutinized among different populations to avoid the potential genetic variations in the primer binding sequences.

Complex transcriptional control of the AZFa gene DDX3Y in human testis

The human DEAD-box Y (DBY) RNA helicase (aka DDX3Y) gene is thought to be the major azoospermia factor a (AZFa) gene in proximal Yq11. Men with its deletion display no somatic pathologies, but suffer from complete absence of germ cells. Accordingly, DDX3Y protein is expressed only in the germline in spermatogonia, although the transcripts were found in many tissues. Here, we show the complex transcriptional control of a testis-specific DDX3Y transcript class with initiation at different sites upstream of the gene’s open reading frame (5′Untranslated Region; UTR) and with polyadenylation in their proximal 3′UTR. The most distal transcriptional start site (TSS; ∼1 kb upstream) was mapped in MSY2, a Y-specific minisatellite. As this testis-specific 5′UTR was subsequently processed by three alternative splicing events, it has been tentatively designated ‘exon-T’(estis). The MSY2 sequence unit was also found upstream of the mouse Ddx3y gene. However, only after its tandem amplification on the Y chromosome of Platyrrhini (new world monkeys) and Catarrhini (old world monkeys) did MSY2 become part of a novel distal promoter for DDX3Y expression in testis tissue and provides a second transcriptional start site (T-TSS-II) in Catarrhini. We therefore suggest that the development of a novel distal DDX3Y promoter in primates, which is activated only in testis tissue, is probably part of the gene’s germline translation control.

Translational control of the AZFa gene DDX3Y by 5′UTR exon-T extension

The human DEAD-box Y (DBY) RNA helicase (aka DDX3Y) gene is thought to be the major azoospermia factor a (AZFa) gene in proximal Yq11. Although it is transcribed in many tissues, the protein is expressed only in spermatogonia. In this study, we demonstrate that this translational control mechanism is probably germ cell-specific because of its association with expression of a distinct class of DDX3Y testis transcripts present only in pre- and post-meiotic male germ cells. They are initiated from a second distal DDX3Y promoter domain at two distinct start sites in the gene's 5' untranslated region (UTR) exon-T sequence. With the aid of an EGFP-3xFLAG reporter cassette cloned downstream of DDX3Y minigenes containing exons 1-4 and two different exon-T extensions, we discovered that DDX3Y translation is influenced by the presence of several ATG triplets located in exon-T, thus upstream of the main translational ATG start codon in exon 1. Strong translational repression of the DDX3Y minigene transcripts was observed when they contained the longest exon-T sequence with five upstream ATG triplets (uATGs). The potential formation of complex distinct stem-loop structures serve here as additional repressor element. Only minor translational attenuation was seen for the DDX3Y minigene transcripts when containing the shortest exon-T sequence, that is, starting at first transcriptional start site (coined 'T-TSS-I'). It was completely released after its single uATG was abolished by mutation. As we found DDX3Y transcripts with the longest exon-T sequence predominantly in spermatids, our results suggest that the amount of DDX3Y protein in pre-meiotic germ cells and its absence in post-meiotic germ cells are tightly controlled by the different extensions of exon-T in this germ cell-specific DDX3Y transcript class.

Y chromosome gr/gr deletions are a risk factor for low semen quality

Subfertility affects one in eight couples. In up to 50% of cases, the male partner has low semen quality. Four Y chromosome deletions, i.e. Azoospermia factor a (AZFa), P5/proximal-P1 (AZFb), P5/distal-P1 and AZFc deletions, are established causes of low semen quality. Whether a recently identified partial AZFc deletion, the gr/gr deletion, also causes low semen quality is at present unclear. We used a dual approach to review the effect of the gr/gr deletion on semen quality. First, we conducted a systematic review and meta-analysis of previous association studies, to compare the prevalence of gr/gr deletions between azoo-/oligozoospermic men and normozoospermic men. Secondly, we studied a cohort of 1041 male partners of subfertile couples unselected for semen quality. We employed a cross-sectional design by screening all men for the gr/gr deletion and comparing the semen quality of men with and without the gr/gr deletion. Seven studies were included in the meta-analysis. The gr/gr deletion was significantly more prevalent among azoo-/oligozoospermic men than among normozoospermic men (OR 2.4, 95% CI 1.75-3.30). In our cohort, 25 men carried a gr/gr deletion. Men with this genotype had a lower sperm concentration (median 34 x 10(6)/ml versus 53 x 10(6)/ml, P = 0.017), total sperm count (median 108 x 10(6) versus 152 x 10(6), P = 0.006) and total motile sperm count (median 20 x 10(6) versus 50 x 10(6), P = 0.010) than men without the gr/gr deletion. Y chromosome gr/gr deletions significantly reduce sperm counts and are thus associated with low semen quality.

Study of azoospermia factor-a deletion caused by homologous recombination between the human endogenous retroviral elements and population-specific alleles in Japanese infertile males

To evaluate the relationship between the status of homologous recombination and population-specific alleles in infertile Japanese males with azoospermia factor (AZF)-a deletions and to characterize the clinical features of these patients. Retrospective deletion study in infertile Japanese men. University hospital and reproductive clinic. A total of 931 consecutive patients visiting a male-infertility clinic were genetically evaluated. Patients were analyzed for Y-chromosomal microdeletions and the breakpoints of intrachromosomal homologous recombination of human endogenous retrovirus (HERV) 15qy; in addition, Y-haplogroup typing on the basis of polymerase chain reaction also was performed. Endogenous retroviruses contribute to the evolution of the host genome and can be associated with disease. Presence or absence of appropriately sized polymerase chain reaction products. Four cases of AZFa deletions were found. All patients with AZFa deletions had an azoospermia and breakpoints in the ID2 region of HERV15qy. Three of the four cases were derived from Y-haplogroup D2b. Testicular sperm extraction procedures were performed in three of these four patients, and elongated spermatids were recovered in two. However, no pregnancies were successfully achieved. Y-haplotype D2b, specific for some Japanese clade, may be associated with HERV breakpoints that lead to intrachromosomal homologous recombination. From the clinical point of view, the testicular sperm extraction procedure is not applicable to males with complete AZFa deletions.

A Case of Male Infertility with a Reciprocal Translocation t(X;14)(p11.4;p12)

A chromosomal abnormality was found in about 3.6-7.6% of males presenting with azoospermia or oligospermia. Translocations between X chromosome and autosomes are rarely seen genetic disorders that cause male infertility. We described here a 26-year-old infertile male with t(X;14)(p11.4; p12). He showed a normal phenotype without any familial history of congenital abnormalities. The cytogenetic analysis of the proband revealed an X-autosomal translocation, 46,Y,t(X;14)(p11.4;p12), which was inherited from his mother. The testis biopsies indicated the arrest of spermatogenesis. There were no microdeletions of the azoospermia factor a (AZFa), AZFb and AZFc regions in the Y chromosome shown by PCR with 11 sequence-tagged site (STS) markers. According to the literature, male carriers of an X-autosome translocation are invariably sterile, regardless of the position of the break-point in the X chromosome. To our knowledge, this is the first case report of azoospermia with t(X;14)(p11.4;p12) in Korea.

Cytogenetic and molecular analysis of the Y chromosome: absence of a significant relationship between CAG repeat length in exon 1 of the androgen receptor gene and infertility in Indian men

The genetic basis of male infertility remains unclear in the majority of cases. Recent studies have indicated an association between microdeletions of the azoospermia factor a (AZFa)-AZFc regions of Yq and severe oligospermia or azoospermia. Increased (CAG)n repeat lengths in the androgen receptor (AR) gene have also been reported in infertile men. Therefore, in order to assess the prevalence of these genetic defects to male infertility, 183 men with non-obstructive azoospermia (n = 70), obstructive azoospermia (n = 33), severe oligospermia (n = 80) and 59 fertile men were examined cytogenetically and at molecular level for Yq deletions, microdeletions, and AR-CAG repeat lengths along with hormonal profiles [luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone (T)]. We used high resolution cytogenetics to detect chromosome deletions and multiplex polymerase chain reaction (PCR) involving 27 sequence-tagged site (STS) markers on Yq to determine the rate and extent of Yq microdeletions. PCR amplification with primers flanking exon 1 of AR gene was used to determine the AR-(CAG)n repeat lengths. Hormonal profiles (LH, FSH and T levels) were also analysed in infertile and fertile men. Testicular biopsies showed Sertoli cell only (SCO) morphology, maturation arrests (MA) and hypospermatogenesis. No chromosome aberrations were found in infertile men but there was a significant increase (p < 0.001) in the association of acrocentric chromosomes including the Y chromosome. Yq microdeletions were found in 16 non-obstructive azoospermic men (16 of 70; 22%) and seven severe oligospermic individuals (seven of 80; 8.7%) and most of them had deletions in the sY240 locus. No Yq microdeletions were detected in patients with obstructive azoospermia. No statistically significant difference in the mean length of CAG repeats in AR gene was observed between infertile and fertile men (22.2 +/- 1.5 and 21.5 +/- 1.4 respectively). No significant increase or decrease in levels of LH, FSH and T was observed in infertile and fertile men. In some infertile men, significantly elevated levels of FSH alone or in combination with LH were found to be indicative of failure of spermatogenesis and/or suggestive of testicular failure. Y-chromosome microdeletions contribute to infertility in some patients but no relationship could be established with the (CAG)n repeat lengths in exon 1 of the AR gene in infertile Indian men.