Genetic mutations contributing to non-obstructive azoospermia

Dysregulated expression of IGSF11-AS1 and BVES-AS in azoospermia and its correlation with serum hormone levels

Aim: Azoospermia accounts for 10-20% of male infertility. In 20-30% of affected males, genetic abnormalities are the leading cause of azoospermia. LncRNAs can regulate spermatogenic cell development. Methods: This study chose 76 azoospermia patients and 36 healthy males. The gene expression was examined using the qRT-PCR technique. Results: IGSF11-AS1 and BVES-AS appeared to be considerably underexpressed in the patients; however, only IGSF11-AS1 demonstrated a significant biomarker role. Additionally, IGSF11-AS1 expression was positively correlated with testosterone but was negatively correlated with follicle-stimulating hormone (FSH) and luteinizing hormone (LH). For the BVES-AS gene, however, FSH and LH had a negative correlation. Conclusion: As a result of its low expression level in tissue samples, IGSF11-AS1 has a biomarker role for early azoospermia detection.

USP11 regulates proliferation and apoptosis of human spermatogonial stem cells via HOXC5-mediated canonical WNT/β-catenin signaling pathway

Spermatogonial stem cells (SSCs) are capable of transmitting genetic information to the next generations and they are the initial cells for spermatogenesis. Nevertheless, it remains largely unknown about key genes and signaling pathways that regulate fate determinations of human SSCs and male infertility. In this study, we explored the expression, function, and mechanism of USP11 in controlling the proliferation and apoptosis of human SSCs as well as the association between its abnormality and azoospermia. We found that USP11 was predominantly expressed in human SSCs as shown by database analysis and immunohistochemistry. USP11 silencing led to decreases in proliferation and DNA synthesis and an enhancement in apoptosis of human SSCs. RNA-sequencing identified HOXC5 as a target of USP11 in human SSCs. Double immunofluorescence, Co-immunoprecipitation (Co-IP), and molecular docking demonstrated an interaction between USP11 and HOXC5 in human SSCs. HOXC5 knockdown suppressed the growth of human SSCs and increased apoptosis via the classical WNT/β-catenin pathway. In contrast, HOXC5 overexpression reversed the effect of proliferation and apoptosis induced by USP11 silencing. Significantly, lower levels of USP11 expression were observed in the testicular tissues of patients with spermatogenic disorders. Collectively, these results implicate that USP11 regulates the fate decisions of human SSCs through the HOXC5/WNT/β-catenin pathway. This study thus provides novel insights into understanding molecular mechanisms underlying human spermatogenesis and the etiology of azoospermia and it offers new targets for gene therapy of male infertility.

Global Practice Patterns in the Evaluation of Non-Obstructive Azoospermia: Results of a World-Wide Survey and Expert Recommendations

PURPOSE

Non-obstructive azoospermia (NOA) represents the persistent absence of sperm in ejaculate without obstruction, stemming from diverse disease processes. This survey explores global practices in NOA diagnosis, comparing them with guidelines and offering expert recommendations.

MATERIALS AND METHODS

A 56-item questionnaire survey on NOA diagnosis and management was conducted globally from July to September 2022. This paper focuses on part 1, evaluating NOA diagnosis. Data from 367 participants across 49 countries were analyzed descriptively, with a Delphi process used for expert recommendations.

RESULTS

Of 336 eligible responses, most participants were experienced attending physicians (70.93%). To diagnose azoospermia definitively, 81.7% requested two semen samples. Commonly ordered hormone tests included serum follicle-stimulating hormone (FSH) (97.0%), total testosterone (92.9%), and luteinizing hormone (86.9%). Genetic testing was requested by 66.6%, with karyotype analysis (86.2%) and Y chromosome microdeletions (88.3%) prevalent. Diagnostic testicular biopsy, distinguishing obstructive azoospermia (OA) from NOA, was not performed by 45.1%, while 34.6% did it selectively. Differentiation relied on physical examination (76.1%), serum hormone profiles (69.6%), and semen tests (68.1%). Expectations of finding sperm surgically were higher in men with normal FSH, larger testes, and a history of sperm in ejaculate.

CONCLUSIONS

This expert survey, encompassing 367 participants from 49 countries, unveils congruence with recommended guidelines in NOA diagnosis. However, noteworthy disparities in practices suggest a need for evidence-based, international consensus guidelines to standardize NOA evaluation, addressing existing gaps in professional recommendations.

DNM3OS Enhances the Apoptosis and Senescence of Spermatogonia Associated with Nonobstructive Azoospermia by Providing miR-214-5p and Decreasing E2F2 Expression

Background

Nonobstructive azoospermia (NOA) is a complex disease characterized by the spermatogenic dysfunction of testicular tissues. The roles played by long noncoding RNAs (lncRNAs) in NOA pathogenesis have not been extensively studied.

Methods

Microarray assays were performed on samples of testicular biopsy tissue obtained from patients with NOA for the purpose of identifying differentially expressed lncRNAs and messenger RNA (mRNA) transcripts, and the results were verified by quantitative real-time polymerase chain reaction. Mouse-derived GC-1 spermatogonia (spg) cells undergoing treatment with Adriamycin (ADR) were used to investigate the biological functions of the selected lncRNAs in vitro. The target microRNAs (miRNAs) of lncRNAs and the target mRNAs of miRNAs were predicted by a bioinformatics analysis. Functional studies performed using the CCK-8 assay, EdU incorporation assay, apoptosis detection, and senescence-associated β-galactosidase (SA-β-Gal) staining were conducted using GC-1 spg cells.

Results

Totals of 2,652 lncRNAs and 2,625 mRNAs were found to be differentially expressed in the testicular tissue of NOA patients when compared with patients in a control group. Dynamin 3 opposite strand (DNM3OS) was a provider of pe-miR-214-5p that positively regulates miR-214-5p expression in GC-1 spg cells. The E2 factor (E2F) family of transcription factor 2 (E2F2) was initially predicted and subsequently verified to be a downstream gene of miR-214-5p. E2F2 expression was upregulated after DNM3OS knockdown in ADR-treated GC-1 spg cells. Moreover, knockdown of either DNM3OS or miR-214-5p significantly alleviated ADR-induced decreases in cellular activity and proliferation, as well as increases in apoptosis and senescence of mouse spermatogonial GC-1 spg cells.

Conclusions

DNM3OS was found to regulate the apoptosis and senescence of spermatogonia by providing miR-214-5p and decreasing E2F2 expression, suggesting it as a novel target for gene therapy of male infertility.

Novel predictors for livebirth delivery rate in patients with idiopathic non-obstructive azoospermia based on the clinical prediction model

Objective

To build a prediction model for live birth delivery per intracytoplasmic sperm injection (ICSI) in iNOA patients by obtaining sperm by microdissection testicular sperm extraction (mTESE).

Methods

A retrospective cohort study of 377 couples with iNOA male partners treated with 519 mTESE-ICSI cycles was conducted from September 2013 to July 2021 at the Reproductive Medical Centre of Peking University Third Hospital. Following exclusions, 377 couples with iNOA male partners treated with 482 mTESE-ICSIs were included. A prediction model for live birth delivery per ICSI cycle was built by multivariable logistic regression and selected by 10-fold cross-validation. Discrimination was evaluated by c-statistics and calibration was evaluated by the calibration slope.

Results

The live birth delivery rate per mTESE-ICSI cycle was 39.21% (189/482) in these couples. The model identified that the presence of motile sperm during mTESE, bigger testes, higher endometrial thickness on the day of human chorionic gonadotrophin (hCG) administration (ET-hCG), and higher quality embryos are associated with higher live birth delivery success rates. The results of the model were exported based on 10-fold cross-validation. In addition, the area under the mean ROC curve was 0.71 ± 0.05 after 10-fold cross-validation, indicating that the prediction model had certain prediction precision. A calibration plot with an estimated intercept of -1.653 (95% CI: -13.403 to 10.096) and a slope of 1.043 (95% CI: 0.777 to 1.308) indicated that the model was well-calibrated.

Conclusion

Our prediction model will provide valuable information about the chances of live birth delivery in couples with iNOA male partners who have a plan for mTESE-ICSI treatment. Therefore, it can improve and personalize counseling for the medical treatment of these patients.

Male infertility

Clinical infertility is the inability of a couple to conceive after 12 months of trying. Male factors are estimated to contribute to 30-50% of cases of infertility. Infertility or reduced fertility can result from testicular dysfunction, endocrinopathies, lifestyle factors (such as tobacco and obesity), congenital anatomical factors, gonadotoxic exposures and ageing, among others. The evaluation of male infertility includes detailed history taking, focused physical examination and selective laboratory testing, including semen analysis. Treatments include lifestyle optimization, empirical or targeted medical therapy as well as surgical therapies that lead to measurable improvement in fertility. Although male infertility is recognized as a disease with effects on quality of life for both members of the infertile couple, fewer data exist on specific quantification and impact compared with other health-related conditions.

Noninvasive Prediction of Sperm Retrieval Using Diffusion Tensor Imaging in Patients with Nonobstructive Azoospermia

Microdissection testicular sperm extraction (mTESE) is the first-line treatment plan for nonobstructive azoospermia (NOA). However, studies reported that the overall sperm retrieval rate (SRR) was 43% to 63% among men with NOA, implying that nearly half of the patients fail sperm retrieval. This study aimed to evaluate the diagnostic performance of parameters derived from diffusion tensor imaging (DTI) in predicting SRR in patients with NOA. Seventy patients diagnosed with NOA were enrolled and classified into two groups based on the outcome of sperm retrieval during mTESE: success (29 patients) and failure (41 patients). Scrotal magnetic resonance imaging was performed, and the DTI parameters, including mean diffusivity and fractional anisotropy, were analyzed between groups. The results showed that there was a significant difference in mean diffusivity values between the two groups, and the area under the curve for mean diffusivity was calculated as 0.865, with a sensitivity of 72.2% and a specificity of 97.5%. No statistically significant difference was observed in fractional anisotropy values and sex hormone levels between the two groups. This study demonstrated that the mean diffusivity value might serve as a useful noninvasive imaging marker for predicting the SRR of NOA patients undergoing mTESE.

Testicular sperm aspiration has a poor effect in predicting micro-TESE outcomes in NOA patients with AZFc deletion

BACKGROUND

Testicular sperm aspiration (TESA) is widely used in the diagnosis and management of nonobstructive azoospermia. However, its ability for predicting microdissection testicular sperm extraction in nonobstructive azoospermia (NOA) patients with AZFc deletion remains uncertain. To investigate whether TESA affected the sperm retrieval rate (SRR) in NOA patients with AZFc deletion, a retrospective analysis of the clinical data of NOA patients with AZFc deletion who underwent microdissection testicular sperm extraction (micro-TESE) was conducted. The effects of age, testicular volume, follicle-stimulating hormone (FSH) levels, luteinizing hormone (LH) levels, testosterone (T) levels and TESA on the SRR were analyzed in this group of patients.

RESULTS

A total of 181 individuals had their sperm successfully collected and underwent micro-TESE, with an SRR of 67.4%. The patients were separated into two groups based on their micro-TESE results (sperm acquisition and nonsperm acquisition), with no significant variations in age, testicular volume, FSH levels, LH levels, or T levels between the two groups. There was no significant difference in the SRR between any of the groups into which patients were classified based on reproductive hormone reference value ranges. Binary logistic regression was used to explore the absence of significant effects of age, testicular volume, FSH levels, LH levels, and T levels on sperm acquisition in patients undergoing micro-TESE. In the preoperative testicular diagnostic biopsy group, the sperm acquisition and nonsperm acquisition groups had SRRs of 90.1% and 65.1%, respectively. More significantly, there was no significant difference in the SRR between the negative preoperative testicular diagnostic biopsy group and the nonpreoperative testicular diagnostic biopsy group (65.1 vs. 63.8%, p = 0.855).

CONCLUSION

There is a high probability of successful sperm acquisition in the testis of men undergoing micro-TESE. In this group of patients, age, testicular volume, FSH levels, LH levels, and T levels may have little bearing on the micro-TESE outcome. In patients whose preoperative TESA revealed the absence of sperm, the probability of obtaining sperm by micro-TESE remained high (65.1%); negative TESA results appeared to not influence the SRR (63.8%) in patients undergoing micro-TESE.

Proteomic Analysis of Testicular Interstitial Fluid in Men with Azoospermia

Background

The primary microenvironment of the testis comprises testicular interstitial fluid (TIF) surrounding the seminiferous tubules and testicular interstitial tissue. The pathological alterations of germ and Sertoli cells could affect the TIF composition and might contain putative biomarkers for monitoring active spermatogenesis.

Objective

We identified differentially expressed proteins in the TIF of patients with obstructive (OA) or nonobstructive (NOA) azoospermia to elucidate the underlying etiology of defective spermatogenesis.

Design setting and participants

We prospectively enrolled nine patients, including three men with OA and six with NOA with (n = 3) and without (n = 3) successful sperm retrieval. Their TIF was collected during the testicular sperm extraction procedure.

Outcome measurements and statistical analysis

TIF was analyzed using liquid chromatography-tandem mass spectrometry to identify differentially expressed proteins specific to OA and NOA with or without successful sperm retrieval. The dysregulated protein was further validated using Western blotting.

Results and limitations

Among the 555 TIF proteins identified in NOA patients, 14 were downregulated relative to OA patients. These proteins participate in biological processes such as proteolysis, complement activation, and immune responses; complement and coagulation cascade pathways were also enriched. Furthermore, 68 proteins with significantly higher levels were identified in the TIF of NOA patients with successful sperm retrieval than in those with failed sperm retrieval; these are mainly implicated in oxidation-reduction processes. The expression of calreticulin, which can distinguish successful and failed testicular sperm retrieval in the NOA group, was validated by Western blotting.

Conclusions

We provide the first scientific evaluation of TIF protein composition in men with azoospermia. These findings will help identify the physiological and pathological roles of each protein in regulating sperm production. Thus, our study underscores the potential of TIF in sperm retrieval biomarker discovery and would serve as a foundation for further studies to improve treatment strategies against azoospermia.

Patient summary

Using a proteomic approach, we identified and analyzed the total protein content of testicular interstitial fluid in humans with defective spermatogenesis for the first time and discovered altered protein expression patterns in patients with nonobstructive azoospermia (NOA). Proteins related to oxidation-reduction processes were upregulated in NOA patients with successful sperm retrieval compared with those with failed sperm retrieval. This can aid the development of novel diagnostic tools for successful testicular sperm retrieval.

Non-Invasive Diagnostics of Male Spermatogenesis from Seminal Plasma: Seminal Proteins

The compounds of seminal plasma have great potential as biomarkers of male fertility and can be used as a diagnostic tool for types of azoospermia. Azoospermia occurs in approximately 1% of the male population, and for an effective therapy of this form of male infertility, it is important to distinguish between obstructive and non-obstructive azoospermia. Proteins in seminal plasma can serve as biomarkers for diagnosing azoospermia. Considering the various types of obstructions, a combination of multiple proteins is advisable for diagnostic purposes. In this context, testicular and epididymal proteins are particularly significant, as they are specific to these tissues and typically absent in ejaculate during most obstructions. A combination of multiple biomarkers is more effective than the analysis of a single protein. This group of markers contains TEX101 and ECM1 proteins, combined detections of these two bring a diagnostic output with a high sensitivity and specificity. Similar results were observed for combined detection of TEX101 and SPAG1. The effective using of specific biomarkers from seminal plasma can significantly improve the existing approaches to diagnosis of the causes of male infertility.

Identification and validation of diagnostic signature genes in non-obstructive azoospermia by machine learning

Non-obstructive azoospermia (NOA) is a common cause of male infertility, and no specific diagnostic indicators exist. In this study, we used human testis datasets GSE45885, GSE45887, and GSE108886 from GEO database as training datasets, and screened 6 signature genes (all lowly expressed in the NOA group) using Boruta algorithm and Lasso regression: C12orf54, TSSK6, OR2H1, FER1L5, C9orf153, XKR3. The diagnostic efficacy of the above genes was examined by constructing models with LightGBM algorithm: the AUC (Area Under Curve) of both ROC and Precision-Recall curves for internal validation was 1.0 (p < 0.05). For the external validation dataset GSE145467 (human testis), the AUC of its ROC curve was 0.9 and that of its Precision-Recall curve was 0.833 (p < 0.05). Next, we confirmed the cellular localization of the above genes using human testis single-cell RNA sequencing dataset GSE149512, which were all located in spermatid. Besides, the downstream regulatory mechanisms of the above genes in spermatid were inferred by GSEA algorithm: C12orf54 may be involved in the repression of E2F-related and MYC-related pathways, TSSK6 and C9orf153 may be involved in the repression of MYC-related pathways, while FER1L5 may be involved in the repression of spermatogenesis pathway. Finally, we constructed a NOA model in mice using X-ray irradiation, and quantitative Real-time PCR results showed that C12orf54, TSSK6, OR2H1, FER1L5, and C9orf153 were all lowly expressed in NOA group. In summary, we have identified novel signature genes of NOA using machine learning methods and complete experimental validation, which will be helpful for its early diagnosis.

Biallelic variants in KCTD19 associated with male factor infertility and oligoasthenoteratozoospermia

STUDY QUESTION

Can whole-exome sequencing (WES) reveal new genetic factors responsible for male infertility characterized by oligozoospermia?

SUMMARY ANSWER

We identified biallelic missense variants in the Potassium Channel Tetramerization Domain Containing 19 gene (KCTD19) and confirmed it to be a novel pathogenic gene for male infertility.

WHAT IS KNOWN ALREADY

KCTD19 is a key transcriptional regulator that plays an indispensable role in male fertility by regulating meiotic progression. Kctd19 gene-disrupted male mice exhibit infertility due to meiotic arrest.

STUDY DESIGN, SIZE, DURATION

We recruited a cohort of 536 individuals with idiopathic oligozoospermia from 2014 to 2022 and focused on five infertile males from three unrelated families. Semen analysis data and ICSI outcomes were collected. WES and homozygosity mapping were performed to identify potential pathogenic variants. The pathogenicity of the identified variants was investigated in silico and in vitro.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Male patients diagnosed with primary infertility were recruited from the Reproductive and Genetic Hospital of CITIC-Xiangya. Genomic DNA extracted from affected individuals was used for WES and Sanger sequencing. Sperm phenotype, sperm nuclear maturity, chromosome aneuploidy, and sperm ultrastructure were assessed using hematoxylin and eosin staining and toluidine blue staining, FISH and transmission electron microscopy. The functional effects of the identified variants in HEK293T cells were investigated via western blotting and immunofluorescence.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified three homozygous missense variants (NM_001100915, c.G628A:p.E210K, c.C893T:p.P298L, and c.G2309A:p.G770D) in KCTD19 in five infertile males from three unrelated families. Abnormal morphology of the sperm heads with immature nuclei and/or nuclear aneuploidy were frequently observed in individuals with biallelic KCTD19 variants, and ICSI was unable to rescue these deficiencies. These variants reduced the abundance of KCTD19 due to increased ubiquitination and impaired its nuclear colocalization with its functional partner, zinc finger protein 541 (ZFP541), in HEK293T cells.

LIMITATIONS, REASONS FOR CAUTION

The exact pathogenic mechanism remains unclear, and warrants further studies using knock-in mice that mimic the missense mutations found in individuals with biallelic KCTD19 variants.

WIDER IMPLICATIONS OF THE FINDINGS

Our study is the first to report a likely causal relationship between KCTD19 deficiency and male infertility, confirming the critical role of KCTD19 in human reproduction. Additionally, this study provided evidence for the poor ICSI clinical outcomes in individuals with biallelic KCTD19 variants, which may guide clinical treatment strategies.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Key Research and Developmental Program of China (2022YFC2702604 to Y.-Q.T.), the National Natural Science Foundation of China (81971447 and 82171608 to Y.-Q.T., 82101961 to C.T.), a key grant from the Prevention and Treatment of Birth Defects from Hunan Province (2019SK1012 to Y.-Q.T.), a Hunan Provincial Grant for Innovative Province Construction (2019SK4012), and the China Postdoctoral Science Foundation (2022M721124 to W.W.). The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Constructing a seventeen-gene signature model for non-obstructive azoospermia based on integrated transcriptome analyses and WGCNA

BACKGROUND

Non-obstructive azoospermia (NOA) affects approximately 1% of the male population worldwide. The underlying mechanism and gene transcription remain unclear. This study aims to explore the potential pathogenesis for the detection and management of NOA.

METHODS

Based on four microarray datasets from the Gene Expression Omnibus database, integrated analysis and weighted correlation network analysis (WGCNA) were used to obtain the intersected common differentially expressed genes (DESs). Differential signaling pathways were identified via GO and GSVA-KEGG analyses. We constructed a seventeen-gene signature model using least absolute shrinkage and selection operation (LASSO) regression, and validated its efficacy in another two GEO datasets. Three patients with NOA and three patients with obstructive azoospermia were recruited. The mRNA levels of seven key genes were measured in testicular samples, and the gene expression profile was evaluated in the Human Protein Atlas (HPA) database.

RESULTS

In total, 388 upregulated and 795 downregulated common DEGs were identified between the NOA and control groups. ATPase activity, tubulin binding, microtubule binding, and metabolism- and immune-associated signaling pathways were significantly enriched. A seventeen-gene signature predictive model was constructed, and receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) values were 1.000 (training group), 0.901 (testing group), and 0.940 (validation set). The AUCs of seven key genes (REC8, CPS1, DHX57, RRS1, GSTA4, SI, and COX7B) were all > 0.8 in both the testing group and the validation set. The qRT-PCR results showed that consistent with the sequencing data, the mRNA levels of RRS1, GSTA4, and COX7B were upregulated, while CPS1, DHX57, and SI were downregulated in NOA. Four genes (CPS1, DHX57, RRS1, and SI) showed significant differences. Expression data from the HPA database showed the localization characteristics and trajectories of seven key genes in spermatogenic cells, Sertoli cells, and Leydig cells.

CONCLUSIONS

Our findings suggest a novel seventeen-gene signature model with a favorable predictive power, and identify seven key genes with potential as NOA-associated marker genes. Our study provides a new perspective for exploring the underlying pathological mechanism in male infertility.

Novel NLRP14 Mutations Induce Azoospermia

Background. LR family pyrin domain-containing 14 (NLRP14 or NALP14) is one of the important members of the NLR family and was mainly expressed in testis. It is reported that deficiency in the NALP14 gene in mice can cause spermatogenic failure, and several NALP14 mutations have been found in oligospermia and infertile men. Case Presentation. This study reported two novel NALP14 mutations (c.2076delC: p.L697X and c.T2963C: p.F988S) in our patients with azoospermia. The exonic deletion mutation (c.2076delC) and one missense mutation (c.T2963C) were firstly screened out by whole-exome sequencing (WES) and further verified by amplifying and sequencing the specific exons 5 and 10. Histological analysis of testicular biopsy revealed that NALP14 expression was detected strongly in spermatogonia and weakly in early spermatocytes. Additionally, mutations in this gene caused meiotic arrest, and no postmeiotic round spermatids and mature spermatozoa were observed in the seminiferous tubules. Conclusions. This study and previous literatures showed that NLRP14 mutations are closely related to male infertility; we discovered two novel NALP14 mutations and summarized the kinds of literatures on NLRP14 mutations and male infertility. This is the first report that deletion mutation (c.2076delC) and one missense mutation (c.T2963C) in NALP14 all lead to azoospermia, which is still significant to the clinical auxiliary diagnosis of male infertility.

Concomitance of 47,XXY, a balanced reciprocal translocation of t(4;17)(q12;q11.2) encompassing SPINK2 at 4q12 and NOS at 17q11.2 and an AZFa sY86 deletion in an infertile male

OBJECTIVE

We present an infertile male who was incidentally detected to have Klinefelter syndrome, a balanced reciprocal translocation of t(4; 17) (q12; q11.2) and an AZFa sY86 deletion. We review the literature and discuss the significance of 47,XXY, t(4; 17) (q12; q11.2) and AZFa sY86 deletion in this case.

CASE REPORT

A 37-year-old married infertile male was referred for genetic studies of azoospermia. His height was 195 cm and his weight was 85 kg. He had been married for more than one year without any pregnancy in his wife. He was referred for genetic counseling. Cytogenetic analysis revealed a karyotype of 47,XXY,t(4; 17) (q12; q11.2). In addition to Klinefelter syndrome, a balanced reciprocal translocation and an AZFa microdeletion were found. Sequence analysis of SPINK2 and NOS was also performed. These two fertile related genes were located at the breakpoints of translocation respectively. Heterozygosity of single-nucleotide polymorphisms (SNPs) evidenced the presence of two alleles as well as no deletions occurred at the breakpoint regions. An AZF gene analysis revealed a microdeletion at the region of AZFa sY86 region.

CONCLUSION

Genetic analysis of an infertile male may detect multiple factors associated with azoospermia such as translocation, an AZF deletion and Klinefelter syndrome. This case emphasized the importance of tests for chromosomes and AZF deletions among patients with azoospermia. Complete genetic counseling of the consequence of a familial inheritance is also necessary to detect more family carrier members for the prevention of unbalanced chromosome in the offspring.

The '-ics' of male reproduction: genomics, epigenetics, proteomics, metabolomics, and microbiomics

PURPOSE OF REVIEW

To review the most current findings, from the past 2 years, in various '-ics' fields in male infertility, with a specific focus on nonobstructive azoospermia, the most severe form, and varicocele, the most common correctable cause of male infertility.

RECENT FINDINGS

Recent studies confirm previously identified causes and identify previously unknown genetic mutations as causes for nonobstructive azoospermia and varicocele.

SUMMARY

Infertility is a common problem for couples with approximately half of cases attributable to male factor infertility. Although advances in assisted reproductive technology have permitted many more men with infertility to father biological children, the majority of infertile men continue to have unknown causes. The recent explosion of the '-ics' fields, including genomics, epigenetics, proteomics, metabolomics, and microbiomics, has shed light on previously unknown causes for various diseases. New information in these fields will not only shed light on the pathogenesis of these conditions but also may shift the paradigm in clinical testing that may allow clinicians to provide more precise counseling and prognostic information for men with infertility.

Integrative analyses of potential biomarkers and pathways for non-obstructive azoospermia

Background: Non-obstructive azoospermia (NOA) is the most severe form of male infertility. Currently, the molecular mechanisms underlying NOA pathology have not yet been elucidated. Hence, elucidation of the mechanisms of NOA and exploration of potential biomarkers are essential for accurate diagnosis and treatment of this disease. In the present study, we aimed to screen for biomarkers and pathways involved in NOA and reveal their potential molecular mechanisms using integrated bioinformatics. Methods: We downloaded two gene expression datasets from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in NOA and matched the control group tissues were identified using the limma package in R software. Subsequently, Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis (GSEA), protein-protein interaction (PPI) network, gene-microRNAs network, and transcription factor (TF)-hub genes regulatory network analyses were performed to identify hub genes and associated pathways. Finally, we conducted immune infiltration analysis using CIBERSORT to evaluate the relationship between the hub genes and the NOA immune infiltration levels. Results: We identified 698 common DEGs, including 87 commonly upregulated and 611 commonly downregulated genes in the two datasets. GO analysis indicated that the most significantly enriched gene was protein polyglycylation, and KEGG pathway analysis revealed that the DEGs were most significantly enriched in taste transduction and pancreatic secretion signaling pathways. GSEA showed that DEGs affected the biological functions of the ribosome, focaladhesion, and protein_expor. We further identified the top 31 hub genes from the PPI network, and friends analysis of hub genes in the PPI network showed that NR4A2 had the highest score. In addition, immune infiltration analysis found that CD8⁺ T cells and plasma cells were significantly correlated with ODF3 expression, whereas naive B cells, plasma cells, monocytes, M2 macrophages, and resting mast cells showed significant variation in the NR4A2 gene expression group, and there were differences in T cell regulatory immune cell infiltration in the FOS gene expression groups. Conclusion: The present study successfully constructed a regulatory network of DEGs between NOA and normal controls and screened three hub genes using integrative bioinformatics analysis. In addition, our results suggest that functional changes in several immune cells in the immune microenvironment may play an important role in spermatogenesis. Our results provide a novel understanding of the molecular mechanisms of NOA and offer potential biomarkers for its diagnosis and treatment.

Identification of risk genes in Chinese nonobstructive azoospermia patients based on whole-exome sequencing

Nonobstructive azoospermia (NOA) is a severe condition in infertile men, and increasing numbers of causative genes have been identified during the last few decades. Although certain causative genes can explain the presence of NOA in some patients, a proportion of NOA patients remain to be addressed. This study aimed to investigate potential high-risk genes associated with spermatogenesis in idiopathic NOA patients by whole-exome sequencing. Whole-exome sequencing was performed in 46 male patients diagnosed with NOA. First, screening was performed for 119 genes known to be related to male infertility. Next, further screening was performed to determine potential high-risk causative genes for NOA by comparisons with 68 healthy male controls. Finally, risk genes with high/specific expression in the testes were selected and their expression fluctuations during spermatogenesis were graphed. The frequency of cystic fibrosis transmembrane conductance regulator (CFTR) gene pathogenic variant carriers was higher in the NOA patients compared with the healthy controls. Potential risk genes that may be causes of NOA were identified, including seven genes that were highly/specifically expressed in the testes. Four risk genes previously reported to be involved in spermatogenesis (MutS homolog 5 [MSH5], cilia- and flagella-associated protein 54 [CFAP54], MAP7 domain containing 3 [MAP7D3], and coiled-coil domain containing 33 [CCDC33]) and three novel risk genes (coiled-coil domain containing 168 [CCDC168], chromosome 16 open reading frame 96 [C16orf96], and serine protease 48 [PRSS48]) were identified to be highly or specifically expressed in the testes and significantly different in the 46 NOA patients compared with 68 healthy controls. This study on clinical NOA patients provides further evidence for the four previously reported risk genes. The present findings pave the way for further functional investigations and provide candidate risk genes for genetic diagnosis of NOA.

A homozygous missense variant in DND1 causes non-obstructive azoospermia in humans

Non-obstructive azoospermia (NOA) is a severe factor of male infertility; it affects approximately 1% of the global male population and accounts for 40% of male infertility cases. However, the majority of NOA cases remain idiopathic. This is the first study using whole-exome sequencing (WES) to identify a novel missense mutation in the DND1 gene (c.212A&gt;C, p. E71A) from a Pakistani family, that includes three males with NOA. This mutation is predicted to cause DND1 protein misfolding and weaken the DND1 interaction with NANOS2, a significant regulator in primordial germ cell development. Our study identified a DND1 pathogenic mutation in NOA patients and highlighted its critical role in male fertility in humans.

A Gly684Ala substitution in the androgen receptor is the cause for azoospermia in a Chinese family with mild androgen insensitivity syndrome and normal hormone levels

Androgen receptor gene (AR) is essential for male growth and fertility. Its mutations are responsible for androgen insensitivity syndrome (AIS) that usually shows the phenotype of azoospermia resulting in male infertility. This study reported the first case of mild AIS with complete normal serum hormones in a Chinese family. The proband referred for infertility because of azoospermia. His uncle and two cousins are both infertile and have azoospermia. Whole-exome sequencing in the genetic analyses showed that the proband carries a novel hemizygous AR missense mutation, NM_000044.6: c.2051G>C (p.Gly684Ala), in exon four within the ligand-binding domain. His mother and maternal aunt are heterozygous carriers, while his father and brother are wildtype, indicating that the mutation in the proband was inherited from his mother. This pattern is consistent with the genetic model of the X-linked recessive inheritance of AR in AIS pathogenesis. HOPE predicts that p.Gly684Ala increases the hydrophobicity of AR but does not change the AR conformation. PolyPhen-2 predicts that p.Gly684Ala is harmful. This study provides the new knowledge to understand the AR gene mutations in MAIS.

The gene regulatory role of non-coding RNAs in non-obstructive azoospermia

Non-coding RNAs are classified as small non-coding RNAs, long non-coding RNAs and circular RNAs, which are involved in a variety of biological processes, including cell differentiation, proliferation, apoptosis and pathological conditions of various diseases. Many studies have shown that non-coding RNAs are related to spermatogenesis, maturation, apoptosis, function, etc. In addition, the expression of non-coding RNAs in testicular tissue and semen of patients with non-obstructive azoospermia was different. However, the role of non-coding RNAs in the pathogenesis of non-obstructive azoospermia has not been fully elucidated, and the role of non-coding RNAs in non-obstructive azoospermia is rarely reviewed. Here we summarize the research progress of non-coding RNAs in the pathogenesis of non-obstructive azoospermia.

Stem Cell Therapies for Human Infertility: Advantages and Challenges

Physical and mental health and hormonal imbalance are associated with the problems related to infertility and reproductive disorders. The rate of infertility has increased globally over the years, due to various reasons. Given the psychosocial implications of infertility and its effects on the life of the affected people, there has been an increased focus on its treatment over the last several years. Assisted reproductive technology can only solve about 50% of the cases. Moreover, it contains significant risks and does not solve the fundamental problem of infertility. As pluripotent stem cells have the potential to differentiate into almost any type of cell, they have been widely regarded as a promising option in the development of stem cell-based fertility treatments, which could even correct genetic diseases in offspring. These advancements in reproductive biotechnology present both challenges and possibilities for solving infertility problems caused by various unexplainable factors. This review briefly presents the different types of infertility disorders and the potential applications of stem cells in the treatment of these reproductive diseases.

Differential Diagnosis of Azoospermia in Men with Infertility

The differential diagnosis between obstructive and nonobstructive azoospermia is the first step in the clinical management of azoospermic patients with infertility. It includes a detailed medical history and physical examination, semen analysis, hormonal assessment, genetic tests, and imaging studies. A testicular biopsy is reserved for the cases of doubt, mainly in patients whose history, physical examination, and endocrine analysis are inconclusive. The latter should be combined with sperm extraction for possible sperm cryopreservation. We present a detailed analysis on how to make the azoospermia differential diagnosis and discuss three clinical cases where the differential diagnosis was challenging. A coordinated effort involving reproductive urologists/andrologists, geneticists, pathologists, and embryologists will offer the best diagnostic path for men with azoospermia.