Human male infertility associated with mutations in NR5A1 encoding steroidogenic factor 1

Role of NR5A1 Gene Mutations in Disorders of Sex Development: Molecular and Clinical Features

Disorders/differences of sex development (DSDs) are defined as broad, heterogenous groups of congenital conditions characterized by atypical development of genetic, gonadal, or phenotypic sex accompanied by abnormal development of internal and/or external genitalia. NR5A1 gene mutation is one of the principal genetic alterations implicated in causing DSD. This review outlines the role of NR5A1 gene during the process of gonadal development in humans, provides an overview of the molecular and functional characteristics of NR5A1 gene, and discusses potential clinical phenotypes and additional organ diseases due to NR5A1 mutations. NR5A1 mutations were analyzed in patients with 46,XY DSD and 46,XX DSD both during the neonatal and pubertal periods. Loss of function of the NR5A1 gene causes several different phenotypes, including some associated with disease in additional organs. Clinical phenotypes may vary, even among patients carrying the same NR5A1 variant, indicating that there is no specific genotype-phenotype correlation. Genetic tests are crucial diagnostic tools that should be used early in the diagnostic pathway, as early as the neonatal period, when gonadal dysgenesis is the main manifestation of NR5A1 mutation. NR5A1 gene mutations could be mainly associated with amenorrhea, ovarian failure, hypogonadism, and infertility during puberty. Fertility preservation techniques should be considered as early as possible.

Inhibition of p38MAPK signalling pathway alleviates radiation-induced testicular damage through improving spermatogenesis

BACKGROUND AND PURPOSE

Damage to the testis following exposure to ionizing radiation has become an urgent problem to be solved. Here we have investigated if inhibition of p38 mitogen-activated protein kinase (p38MAPK) signalling could alleviate radiation-induced testicular damage.

EXPERIMENTAL APPROACH

In mice exposed to whole body radiation (2-6 Gy), morphological changes of the epididymis and testis was measured by histochemical staining. immunohistochemical and immunofluorescence procedures and western blotting were used to monitor expression and cellular location of proteins. Expression of genes was assessed by qPCR and RNA-Seq was used to profile gene expression.

KEY RESULTS

Exposure to ionizing radiation induced dose-dependent damage to mouse testis. The sperm quality decreased at 6 and 8 weeks after 6 Gy X-ray radiation. Radiation decreased PLZF+ cells and increased SOX9+ cells, and affected the expression of 969 genes, compared with data from non-irradiated mice. Expression of genes related to p38MAPK were enriched by GO analysis and were increased in the irradiated testis, and confirmed by qPCR. Levels of phospho-p38MAPK protein increased at 28 days after irradiation. In irradiated mice, SB203580 treatment increased spermatozoa, SOX9+ cells, the area and diameter of seminiferous tubules, sperm movement rate and density. Furthermore, SB203580 treatment increased SCP3+ cells, accelerating the process of spermatogenesis.

CONCLUSION AND IMPLICATIONS

Exposure to ionizing radiation clearly changed gene expression in mouse testis, involving activation of p38MAPK signalling pathways. Inhibition of p38MAPK by SB203580 partly alleviated the testicular damage caused by radiation and accelerated the recovery of sperms through promoting spermatogenesis.

Clinical and genetic characteristics of a large international cohort of individuals with rare NR5A1/SF-1 variants of sex development

BACKGROUND

Steroidogenic factor 1 (SF-1/NR5A1) is essential for human sex development. Heterozygous NR5A1/SF-1 variants manifest with a broad range of phenotypes of differences of sex development (DSD), which remain unexplained.

METHODS

We conducted a retrospective analysis on the so far largest international cohort of individuals with NR5A1/SF-1 variants, identified through the I-DSD registry and a research network.

FINDINGS

Among 197 individuals with NR5A1/SF-1 variants, we confirmed diverse phenotypes. Over 70% of 46, XY individuals had a severe DSD phenotype, while 90% of 46, XX individuals had female-typical sex development. Close to 100 different novel and known NR5A1/SF-1 variants were identified, without specific hot spots. Additionally, likely disease-associated variants in other genes were reported in 32 individuals out of 128 tested (25%), particularly in those with severe or opposite sex DSD phenotypes. Interestingly, 48% of these variants were found in known DSD or SF-1 interacting genes, but no frequent gene-clusters were identified. Sex registration at birth varied, with <10% undergoing reassignment. Gonadectomy was performed in 30% and genital surgery in 58%. Associated organ anomalies were observed in 27% of individuals with a DSD, mainly concerning the spleen. Intrafamilial phenotypes also varied considerably.

INTERPRETATION

The observed phenotypic variability in individuals and families with NR5A1/SF-1 variants is large and remains unpredictable. It may often not be solely explained by the monogenic pathogenicity of the NR5A1/SF-1 variants but is likely influenced by additional genetic variants and as-yet-unknown factors.

FUNDING

Swiss National Science Foundation (320030-197725) and Boveri Foundation Zürich, Switzerland.

Whole exome data prioritization unveils the hidden weight of Mendelian causes of male infertility. A report from the first Italian cohort

Almost 40% of infertile men cases are classified as idiopathic when tested negative to the current diagnostic routine based on the screening of karyotype, Y chromosome microdeletions and CFTR mutations in men with azoospermia or oligozoospermia. Rare monogenic forms of infertility are not routinely evaluated. In this study we aim to investigate the unknown potential genetic causes in couples with pure male idiopathic infertility by applying variant prioritization to whole exome sequencing (WES) in a cohort of 99 idiopathic Italian patients. The ad-hoc manually curated gene library prioritizes genes already known to be associated with more common and rare syndromic and non-syndromic male infertility forms. Twelve monogenic cases (12.1%) were identified in the whole cohort of patients. Of these, three patients had variants related to mild androgen insensitivity syndrome, two in genes related to hypogonadotropic hypogonadism, and six in genes related to spermatogenic failure, while one patient is mutant in PKD1. These results suggest that NGS combined with our manually curated pipeline for variant prioritization and classification can uncover a considerable number of Mendelian causes of infertility even in a small cohort of patients.

Genetic reanalysis of patients with a difference of sex development carrying the NR5A1/SF-1 variant p.Gly146Ala has discovered other likely disease-causing variations

NR5A1/SF-1 (Steroidogenic factor-1) variants may cause mild to severe differences of sex development (DSD) or may be found in healthy carriers. The NR5A1/SF-1 c.437G>C/p.Gly146Ala variant is common in individuals with a DSD and has been suggested to act as a susceptibility factor for adrenal disease or cryptorchidism. Since the allele frequency is high in the general population, and the functional testing of the p.Gly146Ala variant revealed inconclusive results, the disease-causing effect of this variant has been questioned. However, a role as a disease modifier is still possible given that oligogenic inheritance has been described in patients with NR5A1/SF-1 variants. Therefore, we performed next generation sequencing (NGS) in 13 DSD individuals harboring the NR5A1/SF-1 p.Gly146Ala variant to search for other DSD-causing variants and clarify the function of this variant for the phenotype of the carriers. Panel and whole-exome sequencing was performed, and data were analyzed with a filtering algorithm for detecting variants in NR5A1- and DSD-related genes. The phenotype of the studied individuals ranged from scrotal hypospadias and ambiguous genitalia in 46,XY DSD to opposite sex in both 46,XY and 46,XX. In nine subjects we identified either a clearly pathogenic DSD gene variant (e.g. in AR) or one to four potentially deleterious variants that likely explain the observed phenotype alone (e.g. in FGFR3, CHD7). Our study shows that most individuals carrying the NR5A1/SF-1 p.Gly146Ala variant, harbor at least one other deleterious gene variant which can explain the DSD phenotype. This finding confirms that the NR5A1/SF-1 p.Gly146Ala variant may not contribute to the pathogenesis of DSD and qualifies as a benign polymorphism. Thus, individuals, in whom the NR5A1/SF-1 p.Gly146Ala gene variant has been identified as the underlying genetic cause for their DSD in the past, should be re-evaluated with a NGS method to reveal the real genetic diagnosis.

Case Report: Longitudinal follow-up and testicular sperm extraction in a patient with a pathogenic NR5A1 (SF-1) frameshift variant: p.(Phe70Serfs*5)

Background

Steroidogenic factor 1 (SF-1), encoded by the nuclear receptor subfamily 5 group A member 1 (NR5A1) gene, is a transcriptional factor crucial for adrenal and gonadal organogenesis. Pathogenic variants of NR5A1 are responsible for a wide spectrum of phenotypes with autosomal dominant inheritance including disorders of sex development and oligospermia-azoospermia in 46,XY adults. Preservation of fertility remains challenging in these patients.

Objective

The aim was to offer fertility preservation at the end of puberty in an NR5A1 mutated patient.

Case report

The patient was born of non-consanguineous parents, with a disorder of sex development, a small genital bud, perineal hypospadias, and gonads in the left labioscrotal fold and the right inguinal region. Neither uterus nor vagina was detected. The karyotype was 46,XY. Anti-Müllerian hormone (AMH) and testosterone levels were low, indicating testicular dysgenesis. The child was raised as a boy. At 9 years old, he presented with precocious puberty treated by triptorelin. At puberty, follicle-stimulating hormone (FSH), luteinising hormone (LH), and testosterone levels increased, whereas AMH, inhibin B, and testicular volume were low, suggesting an impaired Sertoli cell function and a partially preserved Leydig cell function. A genetic study performed at almost 15 years old identified the new frameshift variant NM_004959.5: c.207del p.(Phe70Serfs*5) at a heterozygous state. He was thus addressed for fertility preservation. No sperm cells could be retrieved from three semen collections between the ages of 16 years 4 months and 16 years 10 months. A conventional bilateral testicular biopsy and testicular sperm extraction were performed at 17 years 10 months of age, but no sperm cells were found. Histological analysis revealed an aspect of mosaicism with seminiferous tubules that were either atrophic, with Sertoli cells only, or presenting an arrest of spermatogenesis at the spermatocyte stage.

Conclusion

We report a case with a new NR5A1 variant. The fertility preservation protocol proposed at the end of puberty did not allow any sperm retrieval for future parenthood.

Nuclear Receptor Gene Variants Underlying Disorders/Differences of Sex Development through Abnormal Testicular Development

Gonadal development is the first step in human reproduction. Aberrant gonadal development during the fetal period is a major cause of disorders/differences of sex development (DSD). To date, pathogenic variants of three nuclear receptor genes (NR5A1, NR0B1, and NR2F2) have been reported to cause DSD via atypical testicular development. In this review article, we describe the clinical significance of the NR5A1 variants as the cause of DSD and introduce novel findings from recent studies. NR5A1 variants are associated with 46,XY DSD and 46,XX testicular/ovotesticular DSD. Notably, both 46,XX DSD and 46,XY DSD caused by the NR5A1 variants show remarkable phenotypic variability, to which digenic/oligogenic inheritances potentially contribute. Additionally, we discuss the roles of NR0B1 and NR2F2 in the etiology of DSD. NR0B1 acts as an anti-testicular gene. Duplications containing NR0B1 result in 46,XY DSD, whereas deletions encompassing NR0B1 can underlie 46,XX testicular/ovotesticular DSD. NR2F2 has recently been reported as a causative gene for 46,XX testicular/ovotesticular DSD and possibly for 46,XY DSD, although the role of NR2F2 in gonadal development is unclear. The knowledge about these three nuclear receptors provides novel insights into the molecular networks involved in the gonadal development in human fetuses.

Impact of Advanced Paternal Age on Fertility and Risks of Genetic Disorders in Offspring

The average age of fathers at first pregnancy has risen significantly over the last decade owing to various variables, including a longer life expectancy, more access to contraception, later marriage, and other factors. As has been proven in several studies, women over 35 years of age have an increased risk of infertility, pregnancy problems, spontaneous abortion, congenital malformations, and postnatal issues. There are varying opinions on whether a father's age affects the quality of his sperm or his ability to father a child. First, there is no single accepted definition of old age in a father. Second, much research has reported contradictory findings in the literature, particularly concerning the most frequently examined criteria. Increasing evidence suggests that the father's age contributes to his offspring's higher vulnerability to inheritable diseases. Our comprehensive literature evaluation shows a direct correlation between paternal age and decreased sperm quality and testicular function. Genetic abnormalities, such as DNA mutations and chromosomal aneuploidies, and epigenetic modifications, such as the silencing of essential genes, have all been linked to the father's advancing years. Paternal age has been shown to affect reproductive and fertility outcomes, such as the success rate of in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and premature birth rate. Several diseases, including autism, schizophrenia, bipolar disorders, and paediatric leukaemia, have been linked to the father's advanced years. Therefore, informing infertile couples of the alarming correlations between older fathers and a rise in their offspring's diseases is crucial, so that they can be effectively guided through their reproductive years.

Comprehensive molecular analysis identifies eight novel variants in XY females with disorders of sex development

Disorders of sex development (DSD) are a group of clinical conditions with variable presentation and genetic background. Females with or without development of secondary sexual characters and presenting with primary amenorrhea (PA) and a 46,XY karyotype are one of the classified groups in DSD. In this study, we aimed to determine the genetic mutations in 25 females with PA and a 46,XY karyotype to show correlations with their phenotypes. Routine Sanger sequencing with candidate genes like SRY, AR, SRD5A2, and SF1, which are mainly responsible for 46,XY DSD in adolescent females, was performed. In a cohort of 25 patients of PA with 46,XY DSD, where routine Sanger sequencing failed to detect the mutations, next-generation sequencing of a targeted gene panel with 81 genes was used for the molecular diagnosis. The targeted sequencing identified a total of 21 mutations including 8 novel variants in 20 out of 25 patients with DSD. The most frequently identified mutations in our series were in AR (36%), followed by SRD5A2 (20%), SF1 (12%), DHX37 (4%), HSD17B3 (4%), and DMRT2 (4%). We could not find any mutation in the DSD-related genes in five (20%) patients due to complex molecular mechanisms in 46,XY DSD, highlighting the possibility of new DSD genes which are yet to be discovered in these disorders. In conclusion, genetic testing, including cytogenetics and molecular genetics, is important for the diagnosis and management of 46,XY DSD cases.

Exome sequencing and functional analyses revealed CETN1 variants leads to impaired cell division and male fertility

Human spermatogenesis requires an orchestrated expression of numerous genes in various germ cell subtypes. Therefore, the genetic landscape of male infertility is highly complex. Known genetic factors alone account for at least 15% of male infertility. However, ~40% of infertile men remain undiagnosed and are classified as idiopathic infertile men. We performed exome sequencing in 47 idiopathic infertile men (discovery cohort), followed by replication study (40 variants in 33 genes) in 844 infertile men and 709 controls using Sequenom MassARRAY® based genotyping. We report 17 variants in twelve genes that comprise both previously reported (DNAH8, DNAH17, FISP2 and SPEF2) and novel candidate genes (BRDT, CETN1, CATSPERD, GMCL1, SPATA6, TSSK4, TSKS and ZNF318) for male infertility. The latter have a strong biological nexus to human spermatogenesis and their respective mouse knockouts are concordant with human phenotypes. One candidate gene CETN1, identified in this study, was sequenced in another independent cohort of 840 infertile and 689 fertile men. Further, CETN1 variants were functionally characterized using biophysical and cell biology approaches. We demonstrate that CETN1 variant- p.Met72Thr leads to multipolar cells, fragmented nuclei during mitosis leading to cell death and show significantly perturbed ciliary disassembly dynamics. Whereas CETN1-5' UTR variant; rs367716858 leads to loss of a methylation site and increased reporter gene expression in vitro. We report a total of eight novel candidate genes identified by exome sequencing, which may have diagnostic relevance and can contribute to improved diagnostic workup and clinical management of male infertility.

The bibliometric analysis of studies on intracytoplasmic sperm injection from 2002 to 2021

BACKGROUND

Infertility is estimated to occur in 1 out of every 4-7 couples. Intracytoplasmic sperm injection (ICSI), a type of assisted reproduction introduced in 1992, has been used across the world for almost all indications of infertility, yielding high pregnancy rates. There is a growing concern worldwide about ICSI since semen quality has declined in recent years, accompanied with the potential risks of this technology. This study aims to analyze the current status and hotspots of ICSI via a bibliometric analysis.

METHODS

We retrieved publications on ICSI from the Web of Science Core Collection database from 2002 to 2021. CiteSpace was used to summarize knowledge mapping of subject categories, keywords, and co-citation relationships with the strongest citation bursts. VOSviewer was used to explore co-citation and co-occurrence relationships for countries, organizations, references, authors, and keywords.

RESULTS

A total of 8271 publications were analyzed between 2002 and 2021. The major findings are as follows: the USA, China, Italy, Japan, and Belgium are the top five prolific countries. The Free University of Brussels, University of Copenhagen, University of Valencia, Ghent University, and the University of California San Francisco are the top five contributing organizations. Fertility and Sterility and Human Reproduction are the most productive and cited journals. The hotspot topics are risks of ICSI, oocyte preservation, live birth rate, infertile men, and embryo quality in the past two decades.

CONCLUSION

This study presents a research overview of ICSI from different perspectives. These findings will contribute to a better understanding of the current status of ICSI research and provide hotspots and trends for future studies.

Continuous 17α-ethinylestradiol exposure impairs the sperm quality of marine medaka (Oryzias melastigma)

17α-ethinylestradiol (EE2) is an anthropogenic estrogen that is widely used for hormone therapy and oral contraceptives. It was reported that EE2 exposure induced reproductive impairments through processes affecting reproduction behavior and inducing ovotestis. However, the effects of continuous EE2 exposure on the reproductive performance remain largely unknown. In this study, adult marine medaka fish (Oryzias melastigma) were exposed to EE2 (85 ng/L) for one (F₀) and two (F₁) generations. Our results indicate that continuous EE2 exposure reduced fecundity and sperm motility. The testicular transcriptome, followed by bioinformatic analysis revealed the dysregulation of pathways related to steroidogenesis, sperm motility, and reproductive system development. Collectively, our findings indicate that continuous EE2 exposure directly affected sperm quality via the alteration of steroidogenesis and dysregulation of reproductive system development. The identified key factors including DNM1, PINK1, PDE7B, and SLC12A7 can serve as biomarkers to assess EE2-reduced sperm motility.

Two complementary approaches for efficient isolation of Sertoli cells for transcriptomic analysis

Sertoli cells (SCs) are the only somatic cells that reside in seminiferous tubules of testis. They directly interact with and support the development of germ cells, thus have an indispensable role in the process of spermatogenesis. SCs first appear in a proliferative state and then, with the initiation of the first wave of spermatogenesis, progress to a mature “nurturing” state which supports lifelong continuous sperm production. During this development, the SC transcriptome must adapt rapidly as obstacles in SC maturation often result in deficiencies in male fertility. Due to its importance in spermatogenesis, a reliable, rapid, and precise method for the isolation of high purity, viable and unadulterated SC has been largely missing. We have developed an improved method for the preparation of a testicular single cell suspension comprised of two alternative protocols to separate SCs from the rest of the testicular cells by FACS. The first sorting scheme is based on their co-expression of surface specific markers, FSHr and Occludin-1, while the second focuses on the co-staining of SCs with FSHr-specific antibody and Hoechst 33342, which discriminates DNA content of testicular cells. The entire procedure can be completed in less than 3 h which permits the analysis of the development-related transcriptional profile of these cells. Notably, our comparative study showed that this method resulted in a SC transcriptome that is largely comparable to SCs which were briskly isolated due to their cell-specific expression of fluorescent protein. Interestingly, we also show that SCs sorted as FSHr⁺Occludin⁺ cells contained a tangible portion of transcripts from all types of testicular germ cells. Sorting of SCs according to their 2C DNA content significantly reduced the presence of these transcripts, thus seems to be the most suitable approach for accurate determination of the SC transcriptome. We believe that these novel approaches for the isolation of SCs will assist researchers in the elucidation of their function as well as their role in spermatogenesis and disorders related to male infertility.

Early Gonadal Development and Sex Determination in Mammal

Sex determination is crucial for the transmission of genetic information through generations. In mammal, this process is primarily regulated by an antagonistic network of sex-related genes beginning in embryonic development and continuing throughout life. Nonetheless, abnormal expression of these sex-related genes will lead to reproductive organ and germline abnormalities, resulting in disorders of sex development (DSD) and infertility. On the other hand, it is possible to predetermine the sex of animal offspring by artificially regulating sex-related gene expression, a recent research hotspot. In this paper, we reviewed recent research that has improved our understanding of the mechanisms underlying the development of the gonad and primordial germ cells (PGCs), progenitors of the germline, to provide new directions for the treatment of DSD and infertility, both of which involve manipulating the sex ratio of livestock offspring.

The Use of Genetics for Reaching a Diagnosis in XY DSD

Reaching a firm diagnosis is vital for the long-term management of a patient with a difference or disorder of sex development (DSD). This is especially the case in XY DSD where the diagnostic yield is particularly low. Molecular genetic technology is playing an increasingly important role in the diagnostic process, and it is highly likely that it will be used more often at an earlier stage in the diagnostic process. In many cases of DSD, the clinical utility of molecular genetics is unequivocally clear, but in many other cases there is a need for careful exploration of the benefit of genetic diagnosis through long-term monitoring of these cases. Furthermore, the incorporation of molecular genetics into the diagnostic process requires a careful appreciation of the strengths and weaknesses of the evolving technology, and the interpretation of the results requires a clear understanding of the wide range of conditions that are associated with DSD.

The Fate of Leydig Cells in Men with Spermatogenic Failure

The steroidogenic cells in the testicle, Leydig cells, located in the interstitial compartment, play a vital role in male reproductive tract development, maintenance of proper spermatogenesis, and overall male reproductive function. Therefore, their dysfunction can lead to all sorts of testicular pathologies. Spermatogenesis failure, manifested as azoospermia, is often associated with defective Leydig cell activity. Spermatogenic failure is the most severe form of male infertility, caused by disorders of the testicular parenchyma or testicular hormone imbalance. This review covers current progress in knowledge on Leydig cells origin, structure, and function, and focuses on recent advances in understanding how Leydig cells contribute to the impairment of spermatogenesis.

Association of methyltetrahydrofolate reductase gene mutation, homocysteine level with semen quality of Iraqi infertile males

Background

Infertility is very common condition and almost 50% of cases are due to male factors. Several genetic and environmental factors are responsible for the poor quality and reduced number of sperms in several cases of infertility. The present study was designed to investigate the association between semen parameters, homocysteine, and the risk of C677T polymorphism of MTHFR gene in infertile males of Iraqi population.

Methods

This Case–control study has been conducted from February 2019 to July 2021 at a molecular laboratory in the Anatomy and Histology Department/college of Medicine/University of Kufa/Najaf/Iraq. It was composed of 353 infertile male patients. They were divided into five groups: 90 azoospermic, 84 oligospermia, 64 asthenospermic, 50 oligoasthenospermic, and 65 teratospermic with an age range 20–46 years compared with 100 fertile males as control with age range 21–49 years. In order to detect homocysteine levels, we used Hcy ELISA Kit. C677T mutation of MTHFR gene was employed by PCR–RFLP technique.

Results

Our data revealed three genotypes of MTHFR C677T, 167 (47.3%) subjects had CC genotype, 116 (32.9%) subjects had CT genotype and 70 (21.1%) subjects had TT genotype. Furthermore, T allele was associated with higher risk of infertility in all patients groups for any genetic model. In total infertile subjects (codominant model: CT vs. CC, OR = 2.0, 95% C.I = 1.2–3.3, P = 0.011; TT vs. CC, OR = 4.8, 95% C.I = 3.3–8.2, P = 0.0003; dominant model: CT + TT vs. CC, OR = 2.8, 95% C.I = 1.7–4.5, P = 0.0001). Oligoasthenospermic patients associated with higher risk in CT heterozygous genotype (OR = 2.8, 95% C.I = 1.0–4.9, P = 0.03) and TT homozygous of mutant allele (OR = 6.3, 95% C.I = 1.9–9.2, P = 0.002). Homocystein level was elevated in all infertile groups when compared with control group (P < 0.01), but the elevation was marked in oligoasthenospermia group. As well as, the level of Serum Hcy exhibited the highest value in TT mutant genotype (39.7 µmol/ml) followed by CT genotype (28.5 µmol/ml) while the lowest level of Hcy recorded in CC genotype (14.6 µmol/ml) for oligoasthenospermia group.

Conclusions

By relating the MTHFR C677T gene mutation with a higher homocystein level, the results showed that Iraqi males with this mutation are more likely to suffer from infertility.

Pubertal development in 46,XY patients with NR5A1 mutations

PURPOSE

Mutations in the NR5A1 gene, encoding the transcription factor Steroidogenic Factor-1, are associated with a highly variable genital phenotype in patients with 46,XY differences of sex development (DSD). Our objective was to analyse the pubertal development in 46,XY patients with NR5A1 mutations by the evaluation of longitudinal clinical and hormonal data at pubertal age.

METHODS

We retrospectively studied a cohort of 10 46,XY patients with a verified NR5A1 mutation and describe clinical features including the external and internal genitalia, testicular volumes, Tanner stages and serum concentrations of LH, FSH, testosterone, AMH, and inhibin B during pubertal transition.

RESULTS

Patients who first presented in early infancy due to ambiguous genitalia showed spontaneous virilization at pubertal age accompanied by a significant testosterone production despite the decreased gonadal volume. Patients with apparently female external genitalia at birth presented later in life at pubertal age either with signs of virilization and/or absence of female puberty. Testosterone levels were highly variable in this group. In all patients, gonadotropins were constantly in the upper reference range or elevated. Neither the extent of virilization at birth nor the presence of Müllerian structures reliably correlated with the degree of virilization during puberty.

CONCLUSION

Patients with NR5A1 mutations regardless of phenotype at birth may demonstrate considerable virilization at puberty. Therefore, it is important to consider sex assignment carefully and avoid irreversible procedures during infancy.

Updates in Sertoli Cell-Mediated Signaling During Spermatogenesis and Advances in Restoring Sertoli Cell Function

Since their initial description by Enrico Sertoli in 1865, Sertoli cells have continued to enchant testis biologists. Testis size and germ cell carrying capacity are intimately tied to Sertoli cell number and function. One critical Sertoli cell function is signaling from Sertoli cells to germ cells as part of regulation of the spermatogenic cycle. Sertoli cell signals can be endocrine or paracrine in nature. Here we review recent advances in understanding the interplay of Sertoli cell endocrine and paracrine signals that regulate germ cell state. Although these findings have long-term implications for treating male infertility, recent breakthroughs in Sertoli cell transplantation have more immediate implications. We summarize the surge of advances in Sertoli cell ablation and transplantation, both of which are wedded to a growing understanding of the unique Sertoli cell niche in the transitional zone of the testis.

Update on genetic screening and treatment for infertile men with genetic disorders in the era of assisted reproductive technology

A genetic etiology of male infertility is identified in fewer than 25% of infertile men, while 30% of infertile men lack a clear etiology, resulting in a diagnosis of idiopathic male infertility. Advances in reproductive genetics have provided insights into the mechanisms of male infertility, and a characterization of the genetic basis of male infertility may have broad implications for understanding the causes of infertility and determining the prognosis, optimal treatment, and management of couples. In a substantial proportion of patients with azoospermia, known genetic factors contribute to male infertility. Additionally, the number of identified genetic anomalies in other etiologies of male infertility is growing through advances in whole-genome amplification and next-generation sequencing. In this review, we present an up-to-date overview of the indications for appropriate genetic tests, summarize the characteristics of chromosomal and genetic diseases, and discuss the treatment of couples with genetic infertility by microdissection-testicular sperm extraction, personalized hormone therapy, and in vitro fertilization with pre-implantation genetic testing.

Association of X Chromosome Aberrations with Male Infertility

Male infertility is caused by spermatogenetic failure, clinically noted as oligoor azoospermia. Approximately 20% of infertile patients carry a genetic defect. The most frequent genetic defect leading to azoospermia (or severe oligozoospermia) is Klinefelter syndrome (47, XXY), which is numerical chromosomal abnormality and Y- structural chromosome aberration. The human X chromosome is the most stable of all human chromosomes. The X chromosome is loaded with regions of acquired, rapidly evolving genes. The X chromosome may actually play an essential role in male infertility and sperm production. Here we will describe X chromosome aberrations, which are associated with male infertility.

Loss of Ubiquitin Carboxy-Terminal Hydrolase L1 Impairs Long-Term Differentiation Competence and Metabolic Regulation in Murine Spermatogonial Stem Cells

Spermatogonia are stem and progenitor cells responsible for maintaining mammalian spermatogenesis. Preserving the balance between self-renewal of spermatogonial stem cells (SSCs) and differentiation is critical for spermatogenesis and fertility. Ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1) is highly expressed in spermatogonia of many species; however, its functional role has not been identified. Here, we aimed to understand the role of UCH-L1 in murine spermatogonia using a Uch-l1^−/− mouse model. We confirmed that UCH-L1 is expressed in undifferentiated and early-differentiating spermatogonia in the post-natal mammalian testis. The Uch-l1^−/− mice showed reduced testis weight and progressive degeneration of seminiferous tubules. Single-cell transcriptome analysis detected a dysregulated metabolic profile in spermatogonia of Uch-l1^−/− compared to wild-type mice. Furthermore, cultured Uch-l1^−/− SSCs had decreased capacity in regenerating full spermatogenesis after transplantation in vivo and accelerated oxidative phosphorylation (OXPHOS) during maintenance in vitro. Together, these results indicate that the absence of UCH-L1 impacts the maintenance of SSC homeostasis and metabolism and impacts the differentiation competence. Metabolic perturbations associated with loss of UCH-L1 appear to underlie a reduced capacity for supporting spermatogenesis and fertility with age. This work is one step further in understanding the complex regulatory circuits underlying SSC function.

Targeted next-generation sequencing panel screening of 668 Chinese patients with non-obstructive azoospermia

PURPOSE

We aimed (1) to determine the molecular diagnosis rate and the recurrent causative genes of patients with non-obstructive azoospermia (NOA) using targeted next-generation sequencing (NGS) panel screening and (2) to discuss whether these genes help in the prognosis for microsurgical testicular sperm extraction (micro-TESE).

METHODS

We used NGS panels to screen 668 Chinese men with NOA. Micro-TESE outcomes for six patients with pathogenic mutations were followed up. Functional assays were performed for two NR5A1 variants identified: p.I224V and p.R281C.

RESULTS

Targeted NGS panel sequencing could explain 4/189 (2.1% by panel 1) or 10/479 (2.1% by panel 2) of the patients with NOA after exclusion of karyotype abnormalities and Y chromosome microdeletions. Almost all mutations detected were newly described except for NR5A1 p.R281C and TEX11 p.M156V. Two missense NR5A1 mutations-p.R281C and p.I244V-were proved to be deleterious by in vitro functional assays. Mutations in TEX11, TEX14, and NR5A1 genes are recurrent causes of NOA, but each gene explains only a very small percentage (less than 4/668; 0.6%). Only the patient with NR5A1 mutations produced viable spermatozoa through micro-TESE, but other patients with TEX11 and TEX14 had poor micro-TESE prognoses.

CONCLUSIONS

A targeted NGS panel is a feasible diagnostic method for patients with NOA. Because each gene implicated explains only a small proportion of such cases, more genes should be included to further increase the diagnostic rate. Considering previous reports, we suggest that only a few genes that are directly linked to meiosis can indicate poor micro-TESE prognosis, such as TEX11, TEX14, and SYCE1.

Genetic Profiles and Three-year Follow-up Study of Chinese Males With Congenital Hypogonadotropic Hypogonadism

BACKGROUND

The correlation between long-term treatment outcomes with genotypes in congenital hypogonadotropic hypogonadism (CHH) males is rarely reported.

AIM

To investigate the correlations among genotypes, phenotypes, and treatment outcomes for CHH male patients.

METHODS

Whole exome sequencing was performed for 73 Chinese CHH males from one academic center. Patients self-selected one of the 4 treatments: pulsatile Gonadorelin pump (PGP), cyclical gonadotropins therapy (CGT), human menopausal gonadotropin monotherapy, or testosterone replacement treatment. Clinical assessments were performed every 3 months for 3 years.

OUTCOMES

The pathogenicity of variants was determined. Baseline clinical features, spermatogenesis outcomes were analysed.

RESULTS

62 variants were identified in 51 patients (69.9%), 17 of which were novel. Among these mutations, variants on FGFR1, PROKR2, CHD7, ANOS1 and NSMF gene were 16.1%, 16.1%, 11.3%, 8.1% and 8.1% respectively. 11 patients followed the oligogenic pattern (21.6%). All CHD7 patients had hearing impairment, or structural deformities of external/ inner ear and were diagnosed as CHARGE syndrome. 24.7% of CHH patients manifested with ear/hearing anomalies. KS patients had higher rates of cryptorchidism history and ear/hearing anomalies than normosmic CHH subjects. Male patients with PROKR2 mutations showed relatively better testicular development, less dental deformity when compared with FGFR1 mutations. About 30% normosmic patients defined by simple olfactory assessment showed olfactory nerve center (ONC) dysplasia under nasal sinus MRI examination. Among the CHH males treated with CGT or PGP, 70.2% reached spermatogenesis within 3 years of treatment.

CLINICAL IMPLICATIONS

No direct correlation was observed between certain responsible genes and spermatogenic outcomes. When CHH patients were identified with CHD7 variants, ear/hearing evaluation should be carefully performed. The precise assessment of ONC development was advised for normosmic CHH subjects.

STRENGTHS & LIMITATIONS

This study provided informative long-term treatment data of CHH male patients screened with whole exome sequencing. The limitations included small number of subgroups with multifaceted gene variants, clinical heterogeneity, uncontrolled sperm-inducing treatment method. The seventeen novel mutations worth experimental validation in the future.

CONCLUSION

The clinical severity is partially related with specific gene variants, and detailed individualized data and outcomes were provided. Ear/hearing anomalies were closely connected with CHD7 variants, and were common problems for CHH patients. Simple olfactory assessment underestimated the true olfactory deficit. L. Zhang, Y. Gao, Q. Du, et al. Genetic Profiles and Three-year Follow-up Study of Chinese Males With Congenital Hypogonadotropic Hypogonadism. J Sex Med 2021;XX:XXX-XXX.

Pathogenic variants of ATG4D in infertile men with non-obstructive azoospermia identified using whole-exome sequencing

Non-obstructive azoospermia (NOA) is the most severe form of male infertility, and it is primarily associated with genetic defects. We performed whole-exome sequencing of 236 patients with NOA and identified a homozygous pathogenic variant of autophagy-related 4D cysteine peptidase (ATG4D) in two siblings from a consanguineous family and compound heterozygous pathogenic variants of ATG4D in two sporadic cases. The expression of LC3B, a regulator of autophagic activity, was significantly decreased, and the apoptosis rate of spermatogenic cells in testicular tissues was increased. Transfection of GC-2spd cells with a ATG4D mutant plasmid (Flag-Atg4d^mut ) significantly decreased the expression level of Lc3b and increased the rate of apoptosis. Moreover, a pathogenic variant in X-linked ATG4A and compound heterozygous pathogenic variants of ATG4B were identified in one patient each. All novel variants were segregated by disease phenotype and were predicted to be pathogenic. Our findings revealed that autophagy-related cysteine peptidase family genes may play crucial roles in human spermatogenesis and identified ATG4D as a novel candidate gene for male infertility due to NOA.

Genetics of Azoospermia

Azoospermia affects 1% of men, and it can be due to: (i) hypothalamic-pituitary dysfunction, (ii) primary quantitative spermatogenic disturbances, (iii) urogenital duct obstruction. Known genetic factors contribute to all these categories, and genetic testing is part of the routine diagnostic workup of azoospermic men. The diagnostic yield of genetic tests in azoospermia is different in the different etiological categories, with the highest in Congenital Bilateral Absence of Vas Deferens (90%) and the lowest in Non-Obstructive Azoospermia (NOA) due to primary testicular failure (~30%). Whole-Exome Sequencing allowed the discovery of an increasing number of monogenic defects of NOA with a current list of 38 candidate genes. These genes are of potential clinical relevance for future gene panel-based screening. We classified these genes according to the associated-testicular histology underlying the NOA phenotype. The validation and the discovery of novel NOA genes will radically improve patient management. Interestingly, approximately 37% of candidate genes are shared in human male and female gonadal failure, implying that genetic counselling should be extended also to female family members of NOA patients.

Rare missense variant in MSH4 associated with primary gonadal failure in both 46, XX and 46, XY individuals

STUDY QUESTION

Can whole-exome sequencing (WES) reveal a shared pathogenic variant responsible for primary gonadal failure in both male and female patients from a consanguineous family?

SUMMARY ANSWER

Patients with primary ovarian insufficiency (POI) and non-obstructive azoospermia (NOA) were homozygous for the rare missense variant p. S754L located in the highly conserved MSH4 MutS signature motif of the ATPase domain. An oligozoospermic patient was heterozygous for the variant.

WHAT IS KNOWN ALREADY

MSH4 is a meiosis-specific protein expressed at a certain level in the testes and ovaries. Along with its heterodimer partner MSH5, it is responsible for double-strand Holliday junction recognition and stabilization, to ensure accurate chromosome segregation during meiosis. Knockout male and female mice for Msh4 and Msh5 are reportedly infertile due to meiotic arrest. In humans, MSH4 is associated with male and female gonadal failure, with distinct variations in the MutS domain V.

STUDY DESIGN, SIZE, DURATION

This was a retrospective genetics study of a consanguineous family with multiple cases of gonadal failure in both genders. The subject family was recruited in Iran, in 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The proband who is affected by POI, an NOA brother, a fertile sister and their parents were subjected to WES. The discovered variant was validated in these individuals, and the rest of the family was also genotyped by Sanger sequencing. The variant was not detected in 800 healthy Iranian individuals from the Iranome database nor in 30 sporadic NOA and 30 sporadic POI patients. Suggested effect in aberrant splicing was studied by RT-PCR. Moreover, protein homology modeling was used to further investigate the amino acid substitution in silico.

MAIN RESULTS AND THE ROLE OF CHANCE

The discovered variant is very rare and has never been reported in the homozygous state. It occurs in the ATPase domain at Serine 754, the first residue within the highly conserved MutS signature motif, substituting it with a Leucine. All variant effect prediction tools indicated this variant as deleterious. Since the substitution occurs immediately before the Walker B motif at position 755, further investigations based on protein homology were conducted. Considering the modeling results, the nature of the substituted amino acid residue and the distances between p. S754L variation and the residues of the Walker B motif suggested the possibility of conformational changes affecting the ATPase activity of the protein.

LARGE SCALE DATA

We have submitted dbSNP entry rs377712900 to ClinVar under SCV001169709, SCV001169708 and SCV001142647 for oligozoospermia, NOA and POI, respectively.

LIMITATIONS, REASONS FOR CAUTION

Studies in model organisms can shed more light on the role of this variant as our results were obtained by variant effect prediction tools and protein homology modeling.

WIDER IMPLICATIONS OF THE FINDINGS

Identification of variants in meiotic genes should improve genetic counseling for both male and female infertility. Also, as two of our NOA patients underwent testicular sperm extraction (TESE) with no success, ruling out the existence of pathogenic variants in meiotic genes in such patients prior to TESE could prove useful.

STUDY FUNDING/COMPETING INTEREST(S)

This study was financially supported by Royan Institute in Tehran, Iran, and Institut Pasteur in Paris, France. The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Novel Gene Regulation in Normal and Abnormal Spermatogenesis

Spermatogenesis is a complex and dynamic process which is precisely controlledby genetic and epigenetic factors. With the development of new technologies (e.g., single-cell RNA sequencing), increasingly more regulatory genes related to spermatogenesis have been identified. In this review, we address the roles and mechanisms of novel genes in regulating the normal and abnormal spermatogenesis. Specifically, we discussed the functions and signaling pathways of key new genes in mediating the proliferation, differentiation, and apoptosis of rodent and human spermatogonial stem cells (SSCs), as well as in controlling the meiosis of spermatocytes and other germ cells. Additionally, we summarized the gene regulation in the abnormal testicular microenvironment or the niche by Sertoli cells, peritubular myoid cells, and Leydig cells. Finally, we pointed out the future directions for investigating the molecular mechanisms underlying human spermatogenesis. This review could offer novel insights into genetic regulation in the normal and abnormal spermatogenesis, and it provides new molecular targets for gene therapy of male infertility.

Mutational analysis of the GATA4 gene in Chinese men with nonobstructive azoospermia

As a crucial transcription factor for spermatogenesis, GATA-binding protein 4 (GATA4) plays important roles in the functioning of Sertoli and Leydig cells. Conditional knockout of GATA4 in mice results in age-dependent testicular atrophy and loss of fertility. However, whether GATA4 is associated with human azoospermia has not been reported. Herein, we analyzed the GATA4 gene by direct sequencing of samples obtained from 184 Chinese men with idiopathic nonobstructive azoospermia (NOA). We identified a missense mutation (c.191G>A, p.G64E), nine single-nucleotide polymorphisms (SNPs), and one rare variant (c.^*84C>T) in the 3´ untranslated region (UTR). Functional studies demonstrated that the p.G64E mutation did not affect transactivation ability of GATA4 for spermatogenesis-related genes (claudin-11 and steroidogenic acute regulatory protein, Star), and the 3´ UTR rare variant c.^*84C>T did not generate microRNA-binding sites to repress GATA4 expression. To our knowledge, this is thefirst report to investigate the association between GATA4 and azoospermia; our results indicate that mutations in GATA4 may not be pathogenic for NOA in Chinese men.

Next-generation sequencing: toward an increase in the diagnostic yield in patients with apparently idiopathic spermatogenic failure

A large proportion of patients with idiopathic spermatogenic failure (SPGF; oligozoospermia or nonobstructive azoospermia [NOA]) do not receive a diagnosis despite an extensive diagnostic workup. Recent evidence has shown that the etiology remains undefined in up to 75% of these patients. A number of genes involved in germ-cell proliferation, spermatocyte meiotic divisions, and spermatid development have been called into play in the pathogenesis of idiopathic oligozoospermia or NOA. However, this evidence mainly comes from case reports. Therefore, this study was undertaken to identify the molecular causes of SPGF. To accomplish this, 15 genes (USP9Y, NR5A1, KLHL10, ZMYND15, PLK4, TEX15, TEX11, MEIOB, SOHLH1, HSF2, SYCP3, TAF4B, NANOS1, SYCE1, and RHOXF2) involved in idiopathic SPGF were simultaneously analyzed in a cohort of 25 patients with idiopathic oligozoospermia or NOA, accurately selected after a thorough diagnostic workup. After next-generation sequencing (NGS) analysis, we identified the presence of rare variants in the NR5A1 and TEX11 genes with a pathogenic role in 3/25 (12.0%) patients. Seventeen other different variants were identified, and among them, 13 have never been reported before. Eleven out of 17 variants were likely pathogenic and deserve functional or segregation studies. The genes most frequently mutated were MEIOB, followed by USP9Y, KLHL10, NR5A1, and SOHLH1. No alterations were found in the SYCP3, TAF4B, NANOS1, SYCE1, or RHOXF2 genes. In conclusion, NGS technology, by screening a specific custom-made panel of genes, could help increase the diagnostic rate in patients with idiopathic oligozoospermia or NOA.

Current Insights Into Adrenal Insufficiency in the Newborn and Young Infant

Adrenal insufficiency (AI) is a potentially life-threatening condition that can be difficult to diagnose, especially if it is not considered as a potential cause of a child's clinical presentation or unexpected deterioration. Children who present with AI in early life can have signs of glucocorticoid deficiency (hyperpigmentation, hypoglycemia, prolonged jaundice, poor weight gain), mineralocorticoid deficiency (hypotension, salt loss, collapse), adrenal androgen excess (atypical genitalia), or associated features linked to a specific underlying condition. Here, we provide an overview of causes of childhood AI, with a focus on genetic conditions that present in the first few months of life. Reaching a specific diagnosis can have lifelong implications for focusing management in an individual, and for counseling the family about inheritance and the risk of recurrence.

Genes predisposing to syndromic and nonsyndromic infertility: a narrative review

Background

Advanced biological techniques have helped produce more insightful findings on the genetic etiology of infertility that may lead to better management of the condition. This review provides an update on genes predisposing to syndromic and nonsyndromic infertility.

Main body

The review identified 65 genes linked with infertility and infertility-related disorders. These genes regulate fertility. However, mutational loss of the functions of the genes predisposes to infertility. Twenty-three (23) genes representing 35% were linked with syndromic infertility, while 42 genes (65%) cause nonsyndromic infertility. Of the 42 nonsyndromic genes, 26 predispose to spermatogenic failure and sperm morphological abnormalities, 11 cause ovarian failures, and 5 cause sex reversal and puberty delay. Overall, 31 genes (48%) predispose to male infertility, 15 genes (23%) cause female infertility, and 19 genes (29%) predispose to both. The common feature of male infertility was spermatogenic failure and sperm morphology abnormalities, while ovarian failure has been the most frequently reported among infertile females. The mechanisms leading to these pathologies are gene-specific, which, if targeted in the affected, may lead to improved treatment.

Conclusions

Mutational loss of the functions of some genes involved in the development and maintenance of fertility may predispose to syndromic or nonsyndromic infertility via gene-specific mechanisms. A treatment procedure that targets the affected gene(s) in individuals expressing infertility may lead to improved treatment.

Clinical Evaluation of a Custom Gene Panel as a Tool for Precision Male Infertility Diagnosis by Next-Generation Sequencing

BACKGROUND

Up to 15% of couples are infertile and male factor infertility accounts for approximately 50% of these cases. Male infertility is a multifactorial pathological condition. The genetic of male infertility is very complex and at least 2000 genes are involved in its etiology. Genetic testing by next-generation sequencing (NGS) technologies can be relevant for its diagnostic value in male infertile patients. Therefore, the aim of this study was to implement the diagnostic offer with the use of an NGS panel for the identification of genetic variants.

METHODS

We developed an NGS gene panel that we used in 22 male infertile patients. The panel consisted of 110 genes exploring the genetic causes of male infertility; namely spermatogenesis failure due to single-gene mutations, central hypogonadism, androgen insensitivity syndrome, congenital hypopituitarism, and primary ciliary dyskinesia.

RESULTS

NGS and a subsequent sequencing of the positive pathogenic or likely pathogenic variants, 5 patients (23%) were found to have a molecular defect. In particular, pathogenic variants were identified in TEX11, CCDC39, CHD7, and NR5A1 genes. Moreover, 14 variants of unknown significance and 7 novel variants were found that require further functional studies and family segregation.

CONCLUSION

This extended NGS-based diagnostic approach may represent a useful tool for the diagnosis of male infertility. The development of a custom-made gene panel by NGS seems capable of reducing the proportion of male idiopathic infertility.

Genetic disorders and male infertility

Background

At present, one out of six couples is infertile, and in 50% of cases, infertility is attributed to male infertility factors. Genetic abnormalities are found in 10%-20% of patients showing severe spermatogenesis disorders, including non-obstructive azoospermia.

Methods

Literatures covering the relationship between male infertility and genetic disorders or chromosomal abnormalities were studied and summarized.

Main findings Results

Genetic disorders, including Klinefelter syndrome, balanced reciprocal translocation, Robertsonian translocation, structural abnormalities in Y chromosome, XX male, azoospermic factor (AZF) deletions, and congenital bilateral absence of vas deferens were summarized and discussed from a practical point of view. Among them, understanding on AZF deletions significantly changed owing to advanced elucidation of their pathogenesis. Due to its technical progress, AZF deletion test can reveal their delicate variations and predict the condition of spermatogenesis. Thirty-nine candidate genes possibly responsible for azoospermia have been identified in the last 10 years owing to the advances in genome sequencing technologies.

Conclusion

Genetic testing for chromosomes and AZF deletions should be examined in cases of severe oligozoospermia and azoospermia. Genetic counseling should be offered before and after genetic testing.

Mutation in CATIP (C2orf62) causes oligoteratoasthenozoospermia by affecting actin dynamics

BACKGROUND

Oligoteratoasthenozoospermia (OTA) combines deteriorated quantity, morphology and motility of the sperm, resulting in male factor infertility.

METHODS

We used whole genome genotyping and exome sequencing to identify the mutation causing OTA in four men in a consanguineous Bedouin family. We expressed the normal and mutated proteins tagged with c-Myc at the carboxy termini by transfection with pCDNA3.1 plasmid constructs to evaluate the effects on protein stability in HEK293 cells and on the kinetics of actin repolymerisation in retinal pigment epithelium cells. Patients' sperm samples were visualised by transmission electron microscopy to determine axoneme structures and were stained with fluorescent phalloidin to visualise the fibrillar (F)-actin.

RESULTS

A homozygous missense mutation in Ciliogenesis Associated TTC17 Interacting Protein (CATIP): c. T103A, p. Phe35Ile, a gene encoding a protein important in actin organisation and ciliogenesis, was identified as the causative mutation with a LOD score of 3.25. The mutation reduces the protein stability compared with the normal protein. Furthermore, overexpression of the normal protein, but not the mutated protein, inhibits repolymerisation of actin after disruption with cytochalasin D. A high percentage of spermatozoa axonemes from patients have abnormalities, as well as disturbances in the distribution of F-actin.

CONCLUSION

This is the first report of a recessive mutation in CATIP in humans. The identified mutation may contribute to asthenozoospermia by its involvement in actin polymerisation and on the actin cytoskeleton. A mouse knockout homozygote for CATIP was reported to demonstrate male infertility as the sole phenotype.

Cigarette smoking is associated with high level of ferroptosis in seminal plasma and affects semen quality

PURPOSE

The effects of cigarette smoking on male semen quality are controversial, and the molecular mechanisms underlying how cigarette smoking affects semen quality are not clear yet.

METHODS

In this study, semen samples from 70 heavy smokers and 75 non-smokers receiving infertility treatment were included. Basic semen parameters in non-smokers and heavy smokers were evaluated. Levels of glutathione (GSH), lipid reactive oxygen species (ROS), iron and GSH-dependent peroxidase 4 (GPX4) protein level were observed in human seminal plasma and in GC-2Spd cells exposed to cigarette smoke condensate (CSC).

RESULTS

Heavy smokers had significantly higher abnormalities (sperm viability and sperm progressive motility) than non-smoking counterparts. Comparing non-smokers group, GSH level was reduced in the group of heavy smokers (P < 0.05). However, the level of lipid ROS and iron were significantly increased (P < 0.05). Besides, GSH level was reduced following treatment with CSC for 24 h, while lipid ROS and iron levels were increased (P < 0.05). However, the levels were reduced after being co-cultured with Ferrostatin-1 (Fer-1) (P < 0.05). The level of GPX4 protein was reduced after being treated with CSC in 24 h, and increased after being co-cultured with Fer-1(P < 0.05).

CONCLUSION

Cigarette smoking is associated with high level of ferroptosis in seminal plasma and affect semen quality.

Role of genetics and epigenetics in male infertility

Male infertility is a complex condition with a strong genetic and epigenetic background. This review discusses the importance of genetic and epigenetic factors in the pathophysiology of male infertility. The interplay between thousands of genes, the epigenetic control of gene expression, and environmental and lifestyle factors, which influence genetic and epigenetic variants, determines the resulting male infertility phenotype. Currently, karyotyping, Y-chromosome microdeletion screening and CFTR gene mutation tests are routinely performed to investigate a possible genetic aetiology in patients with azoospermia and severe oligozoospermia. However, current testing is limited in its ability to identify a variety of genetic and epigenetic conditions that might be implicated in both idiopathic and unexplained infertility. Several epimutations of imprinting genes and developmental genes have been postulated to be candidate markers for male infertility. As such, development of novel diagnostic panels is essential to change the current landscape with regard to prevention, diagnosis and management. Understanding the underlying genetic mechanisms related to the pathophysiology of male infertility, and the impact of environmental exposures and lifestyle factors on gene expression might aid clinicians in developing individualised treatment strategies.

Development of a novel next-generation sequencing panel for diagnosis of quantitative spermatogenic impairment

PURPOSE

To develop and assess a novel custom next-generation sequencing (NGS) panel for male infertility genetic diagnosis.

METHODS

A total of 241 subjects with diagnosis of idiopathic infertility ranging from azoospermia to normozoospermia were sequenced by a custom NGS panel including AR, FSHB, FSHR, KLHL10, NR5A1, NANOS1, SEPT12, SYCP3, TEX11 genes. Variants with minor allele frequency < 1% were confirmed by Sanger sequencing.

RESULTS

Nineteen missense variants were detected in 23 subjects with abnormal sperm count, whilst no variants were identified in normozoospermic men. Of identified variants, we prioritized variants classified as pathogenic and of uncertain significance (VUS) (63.1%, 12/19). No missense variants were found in males with normal seminal parameters (0/67). Therefore, the prevalence of variants was significantly higher in patients with spermatogenic impairment (16/174 vs 0/67, p = 0.007).

CONCLUSION

This study confirms the utility to apply NGS panel for infertility diagnosis in order to find new genetic variants potentially linked to male infertility with much higher accuracy than standard tests suggested by guidelines. Indeed, based on biological significance, prevalence in the general population and clinical data of patients, it is plausible that identified variants in this study might be linked to quantitative spermatogenic impairment, although further studies are needed.

Long noncoding RNAs expression profile and long noncoding RNA-mediated competing endogenous RNA network in nonobstructive azoospermia patients

Aim: To analyze the expression profile and competing endogenous RNA (ceRNA) network of long noncoding RNAs (lncRNAs) in nonobstructive azoospermia (NOA). Materials & methods: The lncRNA expression profile in NOA was determined by microarray reanalysis. Differential expression analysis was performed by R software. The ceRNA network was constructed using correlation analysis and gene target miRNA prediction. Metascape was used for enrichment analysis. Again ceRNA network was validated by quantitative real-time PCR. Results: Many lncRNAs are differently expressed in NOA. LncRNAs might participate in spermatogenesis through ceRNA mechanism. The ceRNA network included male gamete generation and other pathways. LINC00467 in the network regulated the expression of LRGUK and TDRD6. Conclusion: LncRNAs are involved in NOA and potential biomarkers and therapeutic targets for NOA.

Variation analysis of SOX8 gene in Chinese men with non-obstructive azoospermia or oligozoospermia

Sox8, encoding a SRY-related HMG box transcription factor, is essential in Sertoli cells for germ cell differentiation via regulation of integrity of the blood-testis barrier (BTB) as well as Sertoli-germ cell adhesion. Inactivation of Sox8 gene in mice causes postnatal progressive spermatogenic failure, resulting in male infertility. This study aims to investigate whether variants of SOX8 contribute to pathogenesis of idiopathic non-obstructive azoospermia (NOA) or oligozoospermia. A case-control genetic study was conducted in which all exons and exon-intron boundaries of SOX8 gene were screened in 190 NOA and 139 oligozoospermia cases by Sanger sequencing. The detected variants were examined in 284 normospermic controls. Nine known single-nucleotide polymorphisms (SNPs) of SOX8 gene were identified, and four of them exist simultaneously in oligo/azoospermia patients. A comparison of allele/genotype frequencies of these variants showed no significant difference between oligo/azoospermia cases and controls. The results indicate that deleterious variants in SOX8 gene may not be a common cause for oligo/azoospermia in Chinese men. Considering ethnic diversity, SOX8 could not be ruled out as a candidate gene for male infertility. The role of SOX8-mediated Sertoli cell function and BTB integrity played in the pathogenesis of male infertility needs to be further explored in other populations.

Novel NR5A1 Pathogenic Variants Cause Phenotypic Heterogeneity in 46,XY Disorders of Sex Development

Steroidogenic factor 1 (NR5A1/SF1) is a key transcription factor that is known to regulate the development of adrenal glands and gonads and is also involved in steroidogenesis. Several pathogenic NR5A1 variants have been reported to cause 46,XY disorders of sex development (DSD), with varying clinical phenotypes ranging from hypospadias to complete gonadal dysgenesis. Most often, the primary cause of DSD is due to variants in gene(s) related to gonadal development or the steroidogenic pathway. In the present study, we have analyzed 64 cases of 46,XY DSD for pathogenic NR5A1 variants. We report a total of 3 pathogenic variants of which 2 were novel (p.Gly22Ser and p.Ser143Asn) and 1 was already known (p.Ser32Asn). Functional studies have revealed that the 2 mutations p.Gly22Ser and p.Ser32Asn could significantly affect DNA binding and transactivation abilities. Further, these mutant proteins showed nuclear localization with aggregate formation. The third mutation, p.Ser143Asn, showed unspeckled nuclear localization and normal DNA binding, but the ability of transcriptional activation was significantly reduced. In conclusion, we recommend screening for NR5A1 pathogenic variants in individuals with features of 46,XY DSD for better diagnosis and management.

Genetic Landscape of Nonobstructive Azoospermia and New Perspectives for the Clinic

Nonobstructive azoospermia (NOA) represents the most severe expression of male infertility, involving around 1% of the male population and 10% of infertile men. This condition is characterised by the inability of the testis to produce sperm cells, and it is considered to have an important genetic component. During the last two decades, different genetic anomalies, including microdeletions of the Y chromosome, karyotype defects, and missense mutations in genes involved in the reproductive function, have been described as the primary cause of NOA in many infertile men. However, these alterations only explain around 25% of azoospermic cases, with the remaining patients showing an idiopathic origin. Recent studies clearly suggest that the so-called idiopathic NOA has a complex aetiology with a polygenic inheritance, which may alter the spermatogenic process. Although we are far from a complete understanding of the molecular mechanisms underlying NOA, the use of the new technologies for genetic analysis has enabled a considerable increase in knowledge during the last years. In this review, we will provide a comprehensive and updated overview of the genetic basis of NOA, with a special focus on the possible application of the recent insights in clinical practice.

Sertoli cell ablation and replacement of the spermatogonial niche in mouse

Spermatogonia, which produce sperm throughout the male lifetime, are regulated inside a niche composed of Sertoli cells, and other testis cell types. Defects in Sertoli cells often lead to infertility, but replacement of defective cells has been limited by the inability to deplete the existing population. Here, we use an FDA-approved non-toxic drug, benzalkonium chloride (BC), to deplete testis cell types in vivo. Four days after BC administration, Sertoli cells are preferentially depleted, and can be replaced to promote spermatogenesis from surviving (host) spermatogonia. Seven days after BC treatment, multiple cell types can be engrafted from fresh or cryopreserved testicular cells, leading to complete spermatogenesis from donor cells. These methods will be valuable for investigation of niche-supporting cell interactions, have the potential to lead to a therapy for idiopathic male infertility in the clinic, and could open the door to production of sperm from other species in the mouse.

Sertoli cells and other somatic cells of the testis comprise the germ cell niche and are critical to regulate spermatogenesis. Here the authors present a method in which Sertoli cells are selectively targeted for ablation by the compound benzalkonium chloride (BC) in mice, and the spermatogenic niche is subsequently repopulated in regions that have been affected by BC treatment.

Primary adrenal insufficiency: New genetic causes and their long-term consequences

Primary adrenal insufficiency (PAI) is a potentially life-threatening condition that requires urgent diagnosis and treatment. Whilst the most common causes are congenital adrenal hyperplasia (CAH) in childhood and autoimmune adrenal insufficiency in adolescence and adulthood, more than 30 other physical and genetics cause of PAI have been reported. Reaching a specific diagnosis can have implications for management and for monitoring associated features, as well as for counselling families about recurrence risk in siblings and relatives. Here, we describe some recent insights into the genetics of adrenal insufficiency and associated molecular mechanisms. We discuss (a) the role of the nuclear receptors DAX-1 (NR0B1) and steroidogenic factor-1 (SF-1, NR5A1) in human adrenal and reproductive dysfunction; (b) multisystem growth restriction syndromes due to gain-of-function in the growth repressors CDKN1C (IMAGE syndrome) and SAMD9 (MIRAGE syndrome), or loss of POLE1; (c) nonclassic forms of STAR and P450scc/CYP11A1 insufficiency that present with a delayed-onset adrenal phenotype and represent a surprisingly prevalent cause of undiagnosed PAI; and (d) a new sphingolipidosis causing PAI due to defects in sphingosine-1-phosphate lyase-1 (SGPL1). Reaching a specific diagnosis can have life-long implications for management. In some situations, milder or nonclassic forms of these conditions can first present in adulthood and may have been labelled, "Addison's disease."

Recent advances in mammalian reproductive biology

Reproductive biology is a uniquely important topic since it is about germ cells, which are central for transmitting genetic information from generation to generation. In this review, we discuss recent advances in mammalian germ cell development, including preimplantation development, fetal germ cell development and postnatal development of oocytes and sperm. We also discuss the etiologies of female and male infertility and describe the emerging technologies for studying reproductive biology such as gene editing and single-cell technologies.

Deletion of Ck2β gene causes germ cell development arrest and azoospermia in male mice

Objectives

In humans, non‐obstructive azoospermia (NOA) is a major cause of male infertility. However, the aetiology of NOA is largely unknown. Previous studies reported that protein CK2β was abundantly and broadly expressed in spermatogenic cells. Here, we investigate whether protein CK2β participates in spermatogenesis.

Materials and Methods

In this study, we separated spermatogenic cells using STA‐PUT velocity sedimentation, analysed the expression pattern of protein CK2β by immunoblotting, specifically deleted Ck2β gene in early‐stage spermatogenic cells by crossing Ck2β^fl mice with Stra8‐Cre⁺ mice and validated the knockout efficiency by quantitative RT‐PCR and immunoblotting. The phenotypes of Ck2β^fl/Δ;SCre⁺ mice were studied by immunohistochemistry and immunofluorescence. The molecular mechanisms of male germ cell development arrest were elucidated by immunoblotting and TUNEL assay.

Results

Ablation of Ck2β gene triggered excessive germ cell apoptosis, germ cell development arrest, azoospermia and male infertility. Inactivation of Ck2β gene caused distinctly reduced expression of Ck2α′ gene and CK2α′ protein.

Conclusions

Ck2β is a vital gene for germ cell survival and male fertility in mice.

Clinical Features of Infertile Men Carrying a Chromosome 9 Translocation

Previous studies indicated that chromosome 9 translocations are involved in reduced male fertility and increased chance of miscarriage in the female partner. The aim of this study was to review the clinical features and genetic counselling requirements of infertile men carrying chromosome 9 translocations. This study analyzed fertile-age male carriers of chromosome 9 translocations, and included 12 clinical cases in our hospital. In our cases, three cases had oligozoospermia or severe oligozoospermia, while nine cases had normal semen. Of the latter nine cases, seven were associated with recurrent spontaneous abortions, and two produced a phenotypically normal child as confirmed by amniocentesis. Male chromosome 9 translocations and specific breakpoints from reported papers were searched using PubMed and CNKI database. A literature review identified 76 male patients who carried chromosome 9 translocations. Breakpoints at 9p12, 9p11, 9p10 and 9q34.1 were related to pregestational infertility, while breakpoints at 9p21, 9q10, 9q11, 9q13, 9q21.1, 9q22, 9q22.2, 9q22.3, 9q34, 9q34.2 and 9q34.3 exhibited gestational infertility. Chromosome translocations involving chromosome 9 lead to increased risk of miscarriage. Carriers of chromosome 9 translocations should be counselled to consider in vitro fertilization accompanied by preimplantation genetic diagnosis.