Chromosomal disorders and male infertility

Kinesin-7 CENP-E mediates chromosome alignment and spindle assembly checkpoint in meiosis I

In eukaryotes, meiosis is the genetic basis for sexual reproduction, which is important for chromosome stability and species evolution. The defects in meiosis usually lead to chromosome aneuploidy, reduced gamete number, and genetic diseases, but the pathogenic mechanisms are not well clarified. Kinesin-7 CENP-E is a key regulator in chromosome alignment and spindle assembly checkpoint in cell division. However, the functions and mechanisms of CENP-E in male meiosis remain largely unknown. In this study, we have revealed that the CENP-E gene was highly expressed in the rat testis. CENP-E inhibition influences chromosome alignment and spindle organization in metaphase I spermatocytes. We have found that a portion of misaligned homologous chromosomes is located at the spindle poles after CENP-E inhibition, which further activates the spindle assembly checkpoint during the metaphase-to-anaphase transition in rat spermatocytes. Furthermore, CENP-E depletion leads to abnormal spermatogenesis, reduced sperm count, and abnormal sperm head structure. Our findings have elucidated that CENP-E is essential for homologous chromosome alignment and spindle assembly checkpoint in spermatocytes, which further contribute to chromosome stability and sperm cell quality during spermatogenesis.

Etiology of Male Infertility: an Update

Spermatogenesis is a complex process of germ cell division and differentiation that involves extensive cross-talk between the developing germ cells and the somatic testicular cells. Defective endocrine signaling and/or intrinsic defects within the testes can adversely affect spermatogenic progression, leading to subfertility/infertility. In recent years, male infertility has been recognized as a global public health concern, and research over the last few decades has elucidated the complex etiology of male infertility. Congenital reproductive abnormalities, genetic mutations, and endocrine/metabolic dysfunction have been demonstrated to be involved in infertility/subfertility in males. Furthermore, acquired factors like exposure to environmental toxicants and lifestyle-related disorders such as illicit use of psychoactive drugs have been shown to adversely affect spermatogenesis. Despite the large body of available scientific literature on the etiology of male infertility, a substantial proportion of infertility cases are idiopathic in nature, with no known cause. The inability to treat such idiopathic cases stems from poor knowledge about the complex regulation of spermatogenesis. Emerging scientific evidence indicates that defective functioning of testicular Sertoli cells (Sc) may be an underlying cause of infertility/subfertility in males. Sc plays an indispensable role in regulating spermatogenesis, and impaired functional maturation of Sc has been shown to affect fertility in animal models as well as humans, suggesting abnormal Sc as a potential underlying cause of reproductive insufficiency/failure in such cases of unexplained infertility. This review summarizes the major causes of infertility/subfertility in males, with an emphasis on infertility due to dysregulated Sc function.

Cell-cycle and Age-Related Modulations in Mouse Chromosome Stiffness

The intricate structure of chromosomes is complex, and many aspects of chromosome configuration/organization remain to be fully understood. Measuring chromosome stiffness can provide valuable insights into their structure. However, the nature of chromosome stiffness, whether static or dynamic, remains elusive. In this study, we analyzed chromosome stiffness in MI and MII oocytes. We revealed that MI oocytes had a ten-fold increase in stiffness compared to mitotic chromosomes, whereas chromosome stiffness in MII oocytes was relatively low chromosome. We then investigated the contribution of meiosis-specific cohesin complexes to chromosome stiffness in MI and MII oocytes. Surprisingly, the Young's modulus of chromosomes from the three meiosis-specific cohesin mutants did not exhibit significant differences compared to the wild type, indicating that these proteins may not play a substantial role in determining chromosome stiffness. Additionally, our findings revealed an age-related increase in chromosome stiffness in MI oocytes. Age correlates with elevated DNA damage levels, so we investigated the impact of etoposide-induced DNA damage on chromosome stiffness, discovering a reduction in stiffness in response to such damage in MI oocytes. Overall, our study underscores the dynamic nature of chromosome stiffness, subject to changes influenced by the cell cycle and age.

The Impact of Endometriosis on Pregnancy

Despite the increased frequency of endometriosis, it remains one of the most enigmatic disorders regarding its effects on pregnancy. Endometriosis adversely affects both natural and assisted conception. Impaired folliculogenesis, which causes follicular dysfunction and low egg quality, as well as luteal phase problems, reduced fertilization, and abnormal embryogenesis, are some of the mechanisms advocated to explain reproductive dysfunction. There is a rising need for a comprehensive study of the potential negative consequences of this condition on pregnancy outcomes, including the postpartum period, as more women with a medical history of endometriosis become pregnant. Obstetrical complications (small for gestational age [SGA], cesarean section [CS], miscarriage, hemorrhage, low placental adhesion, and preterm delivery) are statistically elevated in women with endometriosis. Furthermore, ruptured ovarian endometrioma, appendicitis, intestinal perforation, and hemoperitoneum have been described in pregnancy. Obstetricians are largely unfamiliar with these complications, as they have not been thoroughly investigated. The development and pathogenesis of endometriosis is an important field of study and has not yet been fully elucidated. Finding these mechanisms is crucial for the development of new and more effective strategies to treat this condition. Endometriosis can have an impact on obstetric and neonatal outcomes of pregnancy, in addition to its potential effects on conception. To date, no additional monitoring is recommended for pregnancies with a history of endometriosis. However, more studies are urgently needed to assess the need for the tailored pregnancy monitoring of women with endometriosis.

Current Applications and Controversies in Preimplantation Genetic Testing for Aneuploidies (PGT-A) in In Vitro Fertilization

Preimplantation genetic testing for aneuploidy (PGT-A) has evolved over recent years, including improvements in embryo culture, biopsy, transfer, and genetic testing. The application of new comprehensive chromosome screening analysis has improved the accuracy in determining the chromosomal status of the analyzed sample, but it has brought new challenges such as the management of partial aneuploidies and mosaicisms. For the past two decades, PGT-A has been involved in a controversy regarding its efficiency in improving IVF outcomes, despite its widespread worldwide implementation. Understanding the impact of embryo aneuploidy in IVF (in vitro fertilization) should theoretically allow improving reproductive outcomes. This review of the literature aims to describe the impact of aneuploidy in human reproduction and how PGT-A was introduced to overcome this obstacle in IVF (in vitro fertilization). The article will try to analyze and summarize the evolution of the PGT-A in the recent years, and its current applications and limitations, as well as the controversy it generates. Conflicting published data could indicate the lacking value of a single biopsied sample to determine embryo chromosomal status and/or the lack of standardized methods for embryo culture and management and genetic analysis among other factors. It has to be considered that PGT-A may not be a universal test to improve the reproductive potential in IVF patients, rather each clinic should evaluate the efficacy of PGT-A in their IVF program based on their population, skills, and limitations.

MGA-seq: robust identification of extrachromosomal DNA and genetic variants using multiple genetic abnormality sequencing

Genomic abnormalities are strongly associated with cancer and infertility. In this study, we develop a simple and efficient method - multiple genetic abnormality sequencing (MGA-Seq) - to simultaneously detect structural variation, copy number variation, single-nucleotide polymorphism, homogeneously staining regions, and extrachromosomal DNA (ecDNA) from a single tube. MGA-Seq directly sequences proximity-ligated genomic fragments, yielding a dataset with concurrent genome three-dimensional and whole-genome sequencing information, enabling approximate localization of genomic structural variations and facilitating breakpoint identification. Additionally, by utilizing MGA-Seq, we map focal amplification and oncogene coamplification, thus facilitating the exploration of ecDNA's transcriptional regulatory function.

Analysis of chromosomal structural variations in patients with recurrent spontaneous abortion using optical genome mapping

Background and aims: Certain chromosomal structural variations (SVs) in biological parents can lead to recurrent spontaneous abortions (RSAs). Unequal crossing over during meiosis can result in the unbalanced rearrangement of gamete chromosomes such as duplication or deletion. Unfortunately, routine techniques such as karyotyping, fluorescence in situ hybridization (FISH), chromosomal microarray analysis (CMA), and copy number variation sequencing (CNV-seq) cannot detect all types of SVs. In this study, we show that optical genome mapping (OGM) quickly and accurately detects SVs for RSA patients with a high resolution and provides more information about the breakpoint regions at gene level. Methods: Seven couples who had suffered RSA with unbalanced chromosomal rearrangements of aborted embryos were recruited, and ultra-high molecular weight (UHMW) DNA was isolated from their peripheral blood. The consensus genome map was created by de novo assembly on the Bionano Solve data analysis software. SVs and breakpoints were identified via alignments of the reference genome GRCh38/hg38. The exact breakpoint sequences were verified using either Oxford Nanopore sequencing or Sanger sequencing. Results: Various SVs in the recruited couples were successfully detected by OGM. Also, additional complex chromosomal rearrangement (CCRs) and four cryptic balanced reciprocal translocations (BRTs) were revealed, further refining the underlying genetic causes of RSA. Two of the disrupted genes identified in this study, FOXK2 [46,XY,t(7; 17)(q31.3; q25)] and PLXDC2 [46,XX,t(10; 16)(p12.31; q23.1)], had been previously shown to be associated with male fertility and embryo transit. Conclusion: OGM accurately detects chromosomal SVs, especially cryptic BRTs and CCRs. It is a useful complement to routine human genetic diagnostics, such as karyotyping, and detects cryptic BRTs and CCRs more accurately than routine genetic diagnostics.

Sperm and Oocyte Chromosomal Abnormalities

Gametogenesis, the process of producing gametes, differs significantly between oocytes and sperm. Most oocytes have chromosomal aneuploidies, indicating that chromosomal aberrations in miscarried and newborn infants are of oocyte origin. Conversely, most structural anomalies are of sperm origin. A prolonged meiotic period caused by increasing female age is responsible for an increased number of chromosomal aberrations. Sperm chromosomes are difficult to analyze because they cannot be evaluated using somatic cell chromosome analysis methods. Nevertheless, researchers have developed methods for chromosome analysis of sperm using the fluorescence in situ hybridization method, hamster eggs, and mouse eggs, allowing for the cytogenetic evaluation of individual sperm. Reproductive medicine has allowed men with severe spermatogenic defects or chromosomal abnormalities to have children. However, using these techniques to achieve successful pregnancies results in higher rates of miscarriages and embryos with chromosomal abnormalities. This raises questions regarding which cases should undergo sperm chromosome analysis and how the results should be interpreted. Here, we reviewed clinical trials that have been reported on oocyte and sperm chromosome analyses. Examination of chromosomal abnormalities in gametes is critical in assisted reproductive technology. Therefore, it is necessary to continue to study the mechanism underlying gametic chromosomal abnormalities.

Towards a Multi-Omics of Male Infertility

Infertility is a common problem affecting one in six couples and in 30% of infertile couples, the male factor is a major cause. A large number of genes are involved in spermatogenesis and a significant proportion of male infertility phenotypes are of genetic origin. Studies on infertility have so far primarily focused on chromosomal abnormalities and sequence variants in protein-coding genes and have identified a large number of disease-associated genes. However, it has been shown that a multitude of factors across various omics levels also contribute to infertility phenotypes. The complexity of male infertility has led to the understanding that an integrated, multi-omics analysis may be optimal for unravelling this disease. While there is a vast array of different factors across omics levels associated with infertility, the present review focuses on known factors from the genomics, epigenomics, transcriptomics, proteomics, metabolomics, glycomics, lipidomics, miRNomics, and integrated omics levels. These include: repeat expansions in AR, POLG, ATXN1, DMPK, and SHBG, multiple SNPs, copy number variants in the AZF region, disregulated miRNAs, altered H3K9 methylation, differential MTHFR, MEG3, PEG1, and LIT1 methylation, altered protamine ratios and protein hypo/hyperphosphorylation. This integrative review presents a step towards a multi-omics approach to understanding the complex etiology of male infertility. Currently only a few genetic factors, namely chromosomal abnormalities and Y chromosome microdeletions, are routinely tested in infertile men undergoing intracytoplasmic sperm injection. A multi-omics approach to understanding infertility phenotypes may yield a more holistic view of the disease and contribute to the development of improved screening methods and treatment options. Therefore, beside discovering as of yet unknown genetic causes of infertility, integrating multiple fields of study could yield valuable contributions to the understanding of disease development. Future multi-omics studies will enable to synthesise fragmented information and facilitate biomarker discovery and treatments in male infertility.

In silico exploration and molecular dynamics of deleterious SNPs on the human TERF1 protein triggering male infertility

By limiting chromosome erosion and end-to-end fusions, telomere integrity is critical for chromosome stability and cell survival. During mitotic cycles or due to environmental stresses, telomeres become progressively shorter and dysfunctional, thus triggering cellular senescence, genomic instability and cell death. To avoid such consequences, the telomerase action, as well as the Shelterin and CST complexes, assure the telomere's protection. Telomeric repeat binding factor 1 (TERF1), which is one of the primary components of the Shelterin complex, binds directly to the telomere and controls its length and function by regulating the telomerase activity. Several reports about TERF1 gene variations have been associated with different diseases, and some of them have linked these variations to male infertility. Hence, this paper can be advantageous to investigate the association between the missense variants of the TERF1 gene and the susceptibility to male infertility. The stepwise prediction of SNPs pathogenicity followed in this study was based on stability and conservation analysis, post-translational modification, secondary structure, functional interaction prediction, binding energy evaluation and finally molecular dynamic simulation. Prediction matching among the tools revealed that out of 18 SNPs, only four (rs1486407144, rs1259659354, rs1257022048 and rs1320180267) were predicted as the most damaging and highly deleterious SNPs affecting the TERF1 protein and its molecular dynamics when interacting with the TERB1 protein by influencing the function, structural stability, flexibility and compaction of the overall complex. Interestingly, these polymorphisms should be considered during genetic screening so they can be used effectively as genetic biomarkers for male infertility diagnosis.Communicated by Ramaswamy H. Sarma.

Antigen Unmasking Is Required to Clinically Assess Levels and Localisation Patterns of Phospholipase C Zeta in Human Sperm

Mammalian oocyte activation is initiated by intracellular calcium (Ca2+) oscillations, driven by the testis-specific phospholipase C zeta (PLCζ). Sperm PLCζ analysis represents a diagnostic measure of sperm fertilisation capacity. The application of antigen unmasking/retrieval (AUM) generally enhanced the visualisation efficacy of PLCζ in mammalian sperm, but differentially affected the PLCζ profiles in sperm from different human males. It is unclear whether AUM affects the diagnosis of PLCζ in human sperm. Herein, we examined whether the application of AUM affected the correlation of PLCζ profiles with sperm parameters and fertilisation capacity. PLCζ fluorescence levels and localisation patterns were examined within the sperm of males undergoing fertility treatment (55 patients aged 29-53) using immunofluorescence in the absence/presence of AUM. The changes in PLCζ profiles following AUM were examined in relation to sperm health and fertilisation outcome. AUM enhanced the observable levels and specific localisation patterns of PLCζ in relation to both optimal sperm parameters and fertilisation outcome, without which significant differences were not observed. The extent of the change in levels and localisation ratios of PLCζ was also affected to a larger degree in terms of the optimal parameters of sperm fertility and fertilisation capacity by AUM. Collectively, AUM was essential to accurately assesses PLCζ in human sperm in both scientific and clinical contexts.

Advanced sperm tests and impact on clinical male factor management

PURPOSE OF REVIEW

Although semen analysis remains a cornerstone of male fertility evaluation, conventional semen analysis parameters do not assess for DNA integrity or functional capacity of sperm. Sperm DNA fragmentation (SDF) and sperm aneuploidy tests have been utilized as adjunct tools to distinguish fertile and infertile men and predict pregnancy outcomes. This review serves as an update on indications and utility of advanced sperm tests, as well as associated controversies and limitations.

RECENT FINDINGS

Elevated SDF is associated with prolonged time to pregnancy, lower chance of spontaneous pregnancy, and lower live birth rates. Sperm aneuploidy is more frequent in infertile men, in male partners of couples experiencing recurrent pregnancy loss, and recurrent failure of assisted reproductive technology (ART). These tests can, therefore, provide important information to guide management and counseling of infertile couples to optimize reproductive outcomes.

SUMMARY

We evaluated data surrounding SDF and sperm aneuploidy tests, which are utilized both within and beyond the scope of AUA/ASRM guidelines. While the tests at hand require further standardization and randomized controlled studies, the current data suggest strong associations with pregnancy outcomes and can be utilized to counsel and manage infertile males.

Impact of tobacco smoking in association with H2BFWT, PRM1 and PRM2 genes variants on male infertility

Tobacco's genotoxic components can cause a wide range of gene defects in spermatozoa such as single- or double-strand DNA breaks, cross-links, DNA-adducts, higher frequencies of aneuploidy and chromosomal abnormalities. The aim in this study was to determine the correlation between sperm quality determined by standard parameters, sperm DNA maturity tested by Chromomycin A3 (CMA3) staining, sperm DNA fragmentation tested by TUNEL assay and tobacco smoking in association with the single nucleotides polymorphisms (SNP) of three nuclear protein genes in spermatozoa (H2BFWT, PRM1 and PRM2). In this study, semen samples of 167 male patients were collected and divided into 54 non-smokers and 113 smokers. The target sequences in the extracted sperm DNA were amplified by PCR followed by Sanger sequencing. The results showed the presence of three variants: rs7885967, rs553509 and rs578953 in H2BFWT gene in the study population. Only one variant rs737008 was detected in PRM1 gene, and three variants were detected in the PRM2 gene: rs2070923, rs1646022 and rs424908. No significant association was observed between the concentration, progressive motility, morphology and the occurrence of H2BFWT, PRM1 and PRM2 SNPs. However, sperm parameters were significantly lower in heavy smokers compared to controls (p < 0.01) (sperm count: 46.00 vs. 78.50 mill/ml, progressive motility: 15.00% vs. 22.00%, and morphology 4.00% vs. 5.00%, respectively). Moreover, the heavy smoker individuals exhibited a considerable increase in CMA3 positivity and sDF compared to non-smokers (p < 0.01) (29.50% vs. 20.50% and 24.50% vs. 12.00%, respectively). In conclusion, smoking altered sperm parameters and sperm DNA integrity, but did not show a linkage with genetic variants in H2BFWT, and protamine genes (PRM1 and PRM2).

Cytogenetic and molecular characterization of a patient having infertility and mild intellectual disability with a very rare unstable ring chromosome 13

INTRODUCTION

Ring chromosomes arise from breakage and fusion at distal regions of short and long arms of the chromosomes. The effect of the ring chromosome on the phenotype may vary widely depending on the amount of the deletion in the chromosomal areas and genes implicated in these regions.

CASE PRESENTATION

We present a 35-year-old male patient with infertility and mild intellectual disability (MID) who has de novo ring 13 (r(13)) chromosomes. To determine chromosomal abnormality, we performed karyotype analysis, Y chromosome microdeletion analysis, FISH, and aCGH techniques.

CONCLUSION

The patient's karyotype analysis result was mos46,XY,r(13)(p13q34)[75]/45,XY,-13[14]/46,XY,dic (13;13)[8]/47,XY,r(13), + r(13)[2]/46,XY,tetrac r(13;13;13;13)[1]. FISH analysis supported the findings of the cytogenetic analysis. Y microdeletion analysis showed that the AZF region was intact. On aCGH analysis, we detected a 1.5 megabase deletion at the end of chromosome 13, including the CHAMP1 gene. The loss of the CHAMP1 gene, in particular, may explain our patient's MID, and the other deleted genes at 13q34 may explain our patient's infertility.

Pseudodicentric Chromosome Originating from an X-Autosome Translocation in a Male Patient with Cryptozoospermia

Genetic factors are responsible for 15% of male infertility conditions. Numerical and structural chromosomal anomalies are validated genetic factors leading to spermatogenic quantitative defects, with a frequency depending on the severity of the phenotype. Among the structural chromosomal rearrangements, dicentric chromosomes are generally observed in robertsonian translocations or in cases of Y chromosome isodicentrics. In X-autosome translocations, male carriers are generally infertile, regardless of the position of the breakpoint, due to interrupted spermatogenesis. We report an infertile man bearing an unusual balanced (X;22) translocation, with a centromeric X breakpoint generating a derivative pseudodicentric chromosome psu dic(22;X). Extensive cytogenetic analyses were necessary to determine the precise nature of the derivative chromosome. The likely cause of the reproductive phenotype of the patient is discussed based on meiotic chromosomal conformation.

Impact of Vitamin C on Gene Expression Profile of Inflammatory and Anti-Inflammatory Cytokines in the Male Partners of Couples with Recurrent Pregnancy Loss

Immune system disorders and increased inflammation in the male reproductive system can lead to fetal risk in the early stages of development and implantation. Antioxidants such as vitamin C can play a protective role against sperm inflammatory reactions. This study aimed to evaluate the effect of vitamin C on the expression of inflammatory and anti-inflammatory cytokine genes in the male partners of couples with recurrent pregnancy loss. In this randomized clinical trial, twenty male partners of couples with RPL were examined for sperm parameters and expression profile of some inflammatory and anti-inflammatory cytokine genes before and after treatment with vitamin C. There was a statistically significant higher rate of normal morphology and sperm concentration in each patient before and after treatment with vitamin C (p ≤ 0.05). The mRNA levels of interleukin 6 and tumor necrosis factor-alpha were significantly decreased in the sperm of patients after treatment with vitamin C compared to before treatment. In contrast, the gene expression levels of interleukin 4 and transforming growth factor-beta showed a significant increase in the sperm of patients after treatment with vitamin C. Oral daily administration of vitamin C may be effective in the fertility potential of male partners of couples with RPL not only through the improvement of the sperm parameters but also by modulating the expression profile of inflammatory and anti-inflammatory genes. Further studies on protein levels are needed to clarify the role of TNF-⍺ and IFN-γ as a prognostic value in evaluating the recurrent abortion risk in infertile male partners. This trial is registered with IRCT20180312039059N1.

Novel exon mutation in SYCE1 gene is associated with non-obstructive azoospermia

Non‐obstructive azoospermia (NOA) is a common cause of male infertility, and genetic problems, such as chromosomal abnormalities and gene mutations, are important causes of NOA. Our centre received a case of NOA, in which no mature sperm was found during microdissection testicular sperm extraction. A postoperative pathological examination revealed that testicular spermatogenesis was blocked. Target region capture combined with high‐throughput sequencing was used to screen for male infertility‐related gene mutations. Sanger sequencing further confirmed that the SYCE1 gene, a central component of the synaptonemal complex (SC) during meiosis, had a homozygous deletion mutation in the tenth exon (c.689_690del; p.F230fs). Through molecular biological studies, we discovered altered expression and nuclear localization of the endogenous mutant SYCE1. To verify the effects in vitro, wild‐ and mutated‐type SYCE1 vectors were constructed and transfected into a human cell line. The results showed that the expression and molecular weight were decreased for SYCE1 containing c.689_690del. In addition, mutated SYCE1 was abnormally located in the cytoplasm rather than in the nucleus. In summary, our research suggests that the novel homozygous mutation (c.689_690del; p.F230fs) altered the SYCE1 expression pattern and may have disturbed SC assembly, leading to male infertility and to a barrier to gamete formation. We reported for the first time that a frameshift mutation occurred in the exon region of SYCE1 in an NOA patient. This study is beneficial for accurate NOA diagnosis and the development of corresponding gene therapy strategies.

Reciprocal translocation and Robertsonian translocation in relation to semen parameters: A retrospective study and systematic review

Reciprocal translocation and Robertsonian translocation are known to be causative factors of male infertility. However, the association between autosomal reciprocal translocation, Robertsonian translocation and semen parameters remains controversial. We performed a retrospective study and systematic review to investigate semen parameters in patients with autosomal reciprocal translocation or Robertsonian translocation. We recruited a total of 1,033 controls, 723 reciprocal translocation carriers and 326 Robertsonian translocation carriers. Men in the control, reciprocal translocation and Robertsonian translocation groups had a median age of 32.0 (95% CI, 32.0-33.0), 32.0 (95% CI, 32.0-33.0) and 33.0 (95% CI, 32.0-33.0) years respectively. Results showed that sperm concentration, total number per ejaculate, total motility, progressive motility of autosomal reciprocal translocation and Robertsonian translocation carriers were statistically lower than controls (p < .001). Eleven studies featuring 794 patients were enrolled in this systematic review. Compared with controls, autosomal reciprocal translocation and Robertsonian translocation carriers showed lower sperm concentration, total motility, progressive motility and normal morphology. Our results support the conclusion that sperm concentration, total number per ejaculate, total motility and progressive motility are significantly lower in autosomal reciprocal translocation and Robertsonian translocation carriers than in controls.

Cytogenetic Studies of 608 Couples with Recurrent Spontaneous Abortions in Northeastern Iran

Background & Objective:

One of the major genetic causes of recurrent spontaneous abortions is parental chromosomal abnormalities. The objectives of the study were to determine, compare and analyze the incidence and distribution of chromosomal abnormalities in couples with recurrent miscarriages from Northeastern Iran.

Methods:

This study was conducted at Ghaem Hospital, Mashhad, Iran. We evaluated karyotype results of 608 couples with history of recurrent spontaneous abortion. The standard method was used for culturing peripheral venous blood lymphocytes.

Results:

Chromosome aberrations were detected in 43 patients (3.54%), including 25 females and 18 males. Structural chromosomal abnormality was detected in 40 cases, including balanced translocations (25 cases), robertsonian translocations (4 cases), inversions (10 cases) and numerical chromosome aberrations (3 cases). Polymorphic variants were observed in 22 individuals.

Conclusion:

The frequency of chromosomal abnormalities in couples with Recurrent Spontaneous Abortion (RSA) in our study is 3.54%. Reciprocal translocation, pericentric inversions, robertsonian translocations, and numerical abnormality observed among couples who had experienced recurrent spontaneous abortions and that these couples might benefit from cytogenetic analysis.

Genetic variations as molecular diagnostic factors for idiopathic male infertility: current knowledge and future perspectives

INTRODUCTION

Infertility is a major health problem, worldwide, which affects 10-15% of couples. About half a percent of infertility cases are related to male-related factors. Male infertility is a complex disease that is the result of various insults as lifestyle issues, genetics, and epigenetic factors. Idiopathic infertility is responsible for 30% of total cases. The genetic factors responsible for male infertility include chromosomal abnormalities, deletions of chromosome Y, and mutations and genetic variations of key genes.

AREAS COVERED

In this review article, we aim to narrate performed studies on polymorphisms of essential genes involved in male infertility including folate metabolizing genes, oxidative stress-related genes, inflammation, and cellular pathways related to spermatogenesis. Moreover, possible pathophysiologic mechanisms responsible for genetic polymorphisms are discussed.

EXPERT OPINION

Analysis and assessment of these genetic variations could help in screening, diagnosis, and treatment of idiopathic male infertility.

FISH and Chimps: Insights into Frequency and Distribution of Sperm Aneuploidy in Chimpanzees (Pan troglodytes)

Numerical chromosomal aberrations in sperm are considered to be a major factor in infertility, early pregnancy loss and syndromes with developmental and cognitive disabilities in mammals, including primates. Despite numerous studies in human and farm animals, the incidence and importance of sperm aneuploidies in non-human primate remains mostly undetermined. Here we investigated the incidence and distribution of sperm aneuploidy in chimpanzees (Pan troglodytes), the species closest to human. We identify evolutionary conserved DNA sequences in human and chimpanzee and selected homologous sub-telomeric regions for all chromosomes to build custom probes and perform sperm-FISH analysis on more than 10,000 sperm nuclei per chromosome. Chimpanzee mean autosomal disomy rate was 0.057 ± 0.02%, gonosomes disomy rate was 0.198% and the total disomy rate was 1.497%. The proportion of X or Y gametes was respectively 49.94% and 50.06% for a ratio of 1.002 and diploidy rate was 0.053%. Our data provide for the first time an overview of aneuploidy in non-human primate sperm and shed new insights into the issues of aneuploidy origins and mechanisms.

Single cell analysis of DNA in more than 10,000 individual sperm from men with abnormal reproductive outcomes

PURPOSE

This pilot study sought to (1) validate the use of a novel technology for single-sperm-cell genome sequencing (Sperm-seq) in infertile men who may not have optimal quantity or quality of sperm for genomic analysis and (2) compare these results to fertile donors.

METHODS

Infertile men undergoing IVF with female partners with a previous history of failed fertilization with ICSI (FF) or poor blastulation of embryos (PB) were recruited from a large IVF center. Sperm-seq was used to analyze thousands of individual sperm and was carried out at an affiliated university research institute. Global aneuploidy rate, crossover locations, and crossover frequencies were assessed in the infertile population, and compared with a control group of 20 fertile donors, which were analyzed previously at the same laboratory.

RESULTS

Eight patients were initially included, but 3 samples did not yield high-quality genomic data for analysis. A total of 10,042 sperm were analyzed from 5 patients, 2 in the FF group, and 3 in the PB group. The global aneuploidy rate among the samples was 2-4%, similar to the control group. Likewise, crossover locations and frequencies were similar.

CONCLUSION

Sperm-seq provides a robust analysis but may not be applicable to all male infertility cases due to technical limitations. This group of male infertility patients did not have higher rates of aneuploidy or abnormal crossover patterns compared to a fertile donor population. Our data may suggest that FF and PB phenotypes may not be related to sperm aneuploidy or meiotic errors but rather to other intrinsic nuclear anomalies.

The Risk of Congenital Anomalies by Fertility Treatment Modality

Importance

Up to 4% of all births in developed nations involve assisted reproductive technology (ART), along with other fertility treatment modalities. Thus, ART pregnancies constitute an important epidemiologic population with a known increased risk of congenital anomalies. In this review, we summarize current fertility treatment modalities and their associated risk of congenital anomalies.

Objective

To review the risk of birth defects among pregnancies conceived with ART and other fertility treatments.

Evidence Acquisition

Articles were obtained from PubMed and the American College of Obstetricians and Gynecologists and American Society of Reproductive Medicine committee opinions.

Results

In vitro fertilization has been associated with a 25% to 50% increased risk of birth defects, including abnormalities of these organ systems: cardiovascular (25%-40% of anomalies), genitourinary (10%-60%), gastrointestinal (10%-20%), and musculoskeletal (10%-35%). Although the data are mixed, intracytoplasmic sperm injection has also been found to be associated with an increased risk of defects, particularly hypospadias, when compared with conventional in vitro fertilization. The risk among fresh versus frozen cycles and cleavage stage versus blastocyst transfers remains uncertain. There appears to be no significant added risk with preimplantation genetic testing, although more studies are needed. Ovulation induction with oral agents appears safe and not associated with an increased risk of anomalies. Oocyte cryopreservation also appears safe, but the data are still limited, requiring future investigation.

Conclusions and Relevance

While the relative risk of birth defects among ART pregnancies is increased when compared with spontaneous conceptions, the absolute risk remains low. There are no standard screening recommendations for ART pregnancies. Per the American College of Obstetricians and Gynecologists, patients who have undergone ART should be counseled regarding the risk of birth defects and available antenatal evaluation, including fetal echocardiogram and detailed ultrasound evaluation.

Association of assisted reproductive technology, germline de novo mutations and congenital heart defects in a prospective birth cohort study

Emerging evidence suggests that children conceived through assisted reproductive technology (ART) have a higher risk of congenital heart defects (CHDs) even when there is no family history. De novo mutation (DNM) is a well-known cause of sporadic congenital diseases; however, whether ART procedures increase the number of germline DNM (gDNM) has not yet been well studied. Here, we performed whole-genome sequencing of 1137 individuals from 160 families conceived through ART and 205 families conceived spontaneously. Children conceived via ART carried 4.59 more gDNMs than children conceived spontaneously, including 3.32 paternal and 1.26 maternal DNMs, after correcting for parental age at conception, cigarette smoking, alcohol drinking, and exercise behaviors. Paternal DNMs in offspring conceived via ART are characterized by C>T substitutions at CpG sites, which potentially affect protein-coding genes and are significantly associated with the increased risk of CHD. In addition, the accumulation of non-coding functional mutations was independently associated with CHD and 87.9% of the mutations were originated from the father. Among ART offspring, infertility of the father was associated with elevated paternal DNMs; usage of both recombinant and urinary follicle-stimulating hormone and high-dosage human chorionic gonadotropin trigger was associated with an increase of maternal DNMs. In sum, the increased gDNMs in offspring conceived by ART were primarily originated from fathers, indicating that ART itself may not be a major reason for the accumulation of gDNMs. Our findings emphasize the importance of evaluating the germline status of the fathers in families with the use of ART.

A rare Y-autosome translocation found in a patient with nonobstructive azoospermia: Case report

Y‑autosome translocations are relatively uncommon in humans, with t(Y;1) stated to be even rarer. On the contrary, pericentric inversion 9 is the most commonly seen inversion  of chromosome . Although considered to have no significant effect on male fertility, the literature reporting on reproductive risks for both aberrations remains controversial. We report here, as far as we know, the first case of a unique combination of balanced reciprocal translocation t(Y;1) with pericentric inversion of chromosome 9 in a patient with nonobstructive azoospermia (NOA) and an otherwise normal phenotype. Our patient was a 37-year-old Caucasian male sent to our Department due to azoospermia reported by semen analysis. The cytogenetic analysis revealed a balanced reciprocal translocation including chromosomes Y and 1 in all observed metaphases: 46, X,t(Y;1)(q12;q21) and a pericentric inversion of chromosome 9: inv(9)(p12q13). By performing metaphase FISH, the t(Y;1) translocation was confirmed. By means of multiplex-PCR, no Y-chromosome microdeletions were detected in the AZF regions. This report demonstrates a unique karyotype showing balanced reciprocal translocation t(Y;1)(q12;q21) with pericentric inversion 9: inv(9)(p12q13), in a patient with NOA, and highlights the importance of appropriate genetic counseling for patients with regard to the medical management of balanced chromosomal aberrations.

A Novel Balanced Chromosomal Translocation in an Azoospermic Male: A Case Report

Background:

Balanced translocation and azoospermia as two main reasons for recurrent pregnancy loss are known to be the leading causes of infertility across the world. Balanced translocations in azoospermic males are very rare and extensive studies need to be performed to elucidate the translocation status of the affected individuals.

Case Presentaion:

The cytogenetic characterization of a 28 year old male and his female partner is reported in this study. The male partner was diagnosed with non-obstructive azoospermia (NOA) and the couple was unable to conceive. Cytogenetic analysis by karyotyping through Giemsa-trypsin-giemsa banding technique (GTG) showed a novel balanced translocation, 46,XY,t(19;22)(19q13.4;22q11.2), 13ps+ in the male and the female karyotype was found to be 46,XX. Multicolor fluorescence in situ hybridization (mFISH) analysis on paternal chromosomal preparations confirmed both the region and origin of balanced translocation. The status of Y chromosome microdeletion (YMD) was analyzed and no notable microdeletion was observed. Furthermore, protein-protein interaction (PPI) network analysis was performed for breakpoint regions to explore the possible functional genetic associations.

Conclusion:

The azoospermic condition of the male patient along with novel balanced chromosomal translocation was responsible for infertility irrespective of its YMD status. Therefore, cytogenetic screening of azoospermic patients should be performed in addition to routine semen analysis to rule out or to confirm presence of any numerical or structural anomaly in the patient.

Underexpression of hsa-miR-449 family and their promoter hypermethylation in infertile men: A case-control study

Background

Post-transcriptional microRNAs (miRNAs) have a impotrant pattern in the spermatogenesis process.

Objective

Study of the expression and methylation of hsa-miR-449 family in sperm samples of infertile men.

Materials and Methods

In this case-control study, we recruited 74 infertile men (with asthenozoospermia, teratozoospermia, asthenoteratozoospermia, and oligoasthenoteratozoospermia) and 30 control samles. Methylation-specific PCR (MSP) method was used for methylation evaluation of hsa-miR-449a, b, c promoter. By Real time PCR (qRT-PCR) method,we showed downregulation of hsa-miR-449a, b, c in the sperm samples of infertile men and compared it to their fertile counterparts.

Results

There was significant underexperssion, in hsa-miR-449-b in oligoasthenoteratospermic samples (p = 0.0001, F = 2.9). About the methylation pattern, infertile men showed high frequency of methylation in the promoter of hsa-miR-449a, b, c in comparison to controls (60.8% vs 23.3%), the highest amount of methylation was observed in oligoasthenoteratospermia samples (81.2%).

Conclusion

In this study, low expression and high methylation of hsa-miR-449-b were observed in infertile men in compared to control samples, which can be one of the causes of defective spermatogenesis.

Frequency of Sperm Aneuploidy in Oligoasthenoteratozoospermic (OAT) Patients by Comprehensive Chromosome Screening: A Proof of Concept

Background:

Embryonic aneuploidy usually results in implantation failure and miscarriage. Considering significantly high frequency of sperm aneuploidy reported in oligoasthenoteratozoospermia (OAT) using fluorescence in situ hybridization (FISH) in limited number of chromosomes and lack of comprehensive chromosome screening (CCS) in OAT, the aim of this study was applying CCS in OAT sperm and comparison of the results with FISH findings.

Methods:

Five OAT patients with normal blood karyotypes and history of implantation failure were included. The successfully amplified samples, each containing two sperm, were analyzed by array comparative genomic hybridization (aCGH). FISH was utilized mainly depending on the aneuploidies found by aCGH to assess their frequencies in total sperm population.

Results:

In aCGH for 30 sperm, aneuploidy was found in 66% of samples. Following the study of 4300 sperm by FISH, an average of 55.46% aneuploidy was observed. No pregnancy was resulted with normal partners.

Conclusion:

Using aCGH, some abnormalities were observed that are not typically considered in sperm FISH studies. Despite small sample size of the comprehensive study, like other similar studies, the frequency of aneuploidies was considerable and similar to FISH. Aneuploidies revealed by aCGH at single sperm resolution were different from sperm population detected by FISH. Considering high frequency of aneuploidy in OATs sperm, preimplantation genetic testing for aneuploidy (PGT-A) can be used for in transfer of chromosomally normal embryos.

Preimplantation genetic testing for aneuploidy in severe male factor infertility

RESEARCH QUESTION

Does the use of preimplantation genetic testing for aneuploidies (PGT-A) improve outcomes in couples with severe male factor infertility (SMFI)?

DESIGN

This retrospective cohort study included SMFI cases that underwent blastocyst transfer with/without PGT-A. Inclusion criteria were SMFI (azoospermia and sperm count <1 million/ml), women aged 25-39 years, single vitrified-warmed blastocyst transfer, and no intracavitary pathologies. Patients were divided into PGT-A and non-PGT-A groups. The primary outcome was live birth rate (live birth of an infant after 24 weeks of gestation); secondary outcomes were implantation and clinical pregnancy rates.

RESULTS

The study included 266 SMFI cases (90 and 176 in the PGT-A and non-PGT-A groups, respectively). Men and women in the PGT-A group were significantly older than those in the non-PGT-A group. The groups did not differ in terms of male factor categories, sperm collection methods or additional female factors. Live birth rates in the PGT-A and non-PGT-A groups were 55.6% and 51.1%, respectively (odds ratio [OR] 1.19, 95% confidence interval [CI] 0.71-1.98, P = 0.495). The implantation rates were 65.6% and 64.2%, respectively (OR 1.06, 95% CI 0.62-1.80, P = 0.827). The clinical pregnancy rates were 62.2% and 58.0%, respectively (OR 1.19, 95% CI 0.71-2.01, P = 0.502). The use of PGT-A was not an independent factor for live birth (aOR 1.33, 95% CI 0.66-2.70, P = 0.421). Advanced age in women was the only independent factor associated with live birth (aOR 0.46, 95% CI 0.22-0.96, P = 0.041).

CONCLUSIONS

The use of PGT-A does not seem to be an independent factor associated with live birth per transfer in couples with SMFI.

Familial Infertility (Azoospermia and Cryptozoospermia) in Two Brothers-Carriers of t(1;7) Complex Chromosomal Rearrangement (CCR): Molecular Cytogenetic Analysis

Structural aberrations involving more than two breakpoints on two or more chromosomes are known as complex chromosomal rearrangements (CCRs). They can reduce fertility through gametogenesis arrest developed due to disrupted chromosomal pairing in the pachytene stage. We present a familial case of two infertile brothers (with azoospermia and cryptozoospermia) and their mother, carriers of an exceptional type of CCR involving chromosomes 1 and 7 and three breakpoints. The aim was to identify whether meiotic disruption was caused by CCR and/or genomic mutations. Additionally, we performed a literature survey for male CCR carriers with reproductive failures. The characterization of the CCR chromosomes and potential genomic aberrations was performed using: G-banding using trypsin and Giemsa staining (GTG banding), fluorescent in situ hybridization (FISH) (including multicolor FISH (mFISH) and bacterial artificial chromosome (BAC)-FISH), and genome-wide array comparative genomic hybridization (aCGH). The CCR description was established as: der(1)(1qter->1q42.3::1p21->1q42.3::7p14.3->7pter), der(7)(1pter->1p2 1::7p14.3->7qter). aCGH revealed three rare genes variants: ASMT, GARNL3, and SESTD1, which were ruled out due to unlikely biological functions. The aCGH analysis of three breakpoint CCR regions did not reveal copy number variations (CNVs) with biologically plausible genes. Synaptonemal complex evaluation (brother-1; spermatocytes II/oligobiopsy; the silver staining technique) showed incomplete conjugation of the chromosomes. Associations between CCR and the sex chromosomes (by FISH) were not found. A meiotic segregation pattern (brother-2; ejaculated spermatozoa; FISH) revealed 29.21% genetically normal/balanced spermatozoa. The aCGH analysis could not detect smaller intergenic CNVs of few kb or smaller (indels of single exons or few nucleotides). Since chromosomal aberrations frequently do not affect the phenotype of the carrier, in contrast to the negative influence on spermatogenesis, there is an obvious need for genomic sequencing to investigate the point mutations that may be responsible for the differences between the azoospermic and cryptozoospermic phenotypes observed in a family. Progeny from the same parents provide a unique opportunity to discover a novel genomic background of male infertility.

Bisexual Fertile Triploid Zebrafish (Danio rerio): a Rare Case

Previous studies have suggested that artificially induced triploid zebrafish are exclusively male-biased. Owing to greatly inhibited gonadal development for the artificially induced triploid fish, they are regarded to be sterile in general. In this article, partially fertile bisexual triploid zebrafish are produced by suppressing extrusion of the second polar body by heat shock. Histological observation confirms that the early gonadal development of these triploid zebrafish is normal. Backcrossing and self-crossing are used to demonstrate that both the female and male triploid zebrafish have partial reproductive ability. Their dynamic of chromosomes during meiosis is revealed from the chromosome preparations of gonads. Examination of the expressed gonadal development-related genes shows some molecular evidence of the normal gonadal development in the triploid zebrafish. Clearly, these fertile bisexual triploid zebrafish can provide a unique system to study sex determination, as well as aneuploidy associated human diseases such as infertility and pregnancy loss.

Phospholipase C zeta profiles are indicative of optimal sperm parameters and fertilisation success in patients undergoing fertility treatment

BACKGROUND

Oocyte activation is driven by intracellular calcium (Ca²⁺ ) oscillations induced by sperm-specific PLCζ, abrogation of which causes oocyte activation deficiency in humans. Clinical PLCζ investigations have been limited to severe male infertility conditions, while PLCζ levels and localisation patterns have yet to be associated with general sperm viability.

MATERIALS AND METHODS

PLCζ profiles were examined within a general population of males attending a fertility clinic (65 patients; aged 29-53), examining PLCζ throughout various fractions of sperm viability. Male recruitment criteria required a minimum sperm count of 5 × 10⁶ spermatozoa/mL, while all female patients included in this study yielded at least five oocytes for treatment. Sperm count, motility and semen volume were recorded according to standard WHO reference guidelines and correlated with PLCζ profiles examined via immunoblotting and immunofluorescence. Appropriate fertility treatments were performed following routine clinical standard operating protocols, and fertilisation success determined by successful observation of second polar body extrusion.

RESULTS AND DISCUSSION

Four distinct PLCζ patterns were observed at the equatorial, acrosomal + equatorial regions of the sperm head, alongside a dispersed pattern, and a population of spermatozoa without any PLCζ. Acrosomal + equatorial PLCζ correlated most to sperm health, while dispersed PLCζ correlated to decreased sperm viability. Total levels of PLCζ exhibited significant correlations with sperm parameters. PLCζ variance corresponded to reduced sperm health, potentially underlying cases of male sub-fertility and increasing male age. Finally, significantly higher levels of PLCζ were exhibited by cases of fertilisation success, alongside higher proportions of Ac + Eq, and lower levels of dispersed PLCζ.

CONCLUSIONS

PLCζ potentially represents a biomarker of sperm health, and fertilisation capacity in general cases of patients seeking fertility treatment, and not just cases of repeated fertilisation. Further focused investigations are required with larger cohorts to examine the full clinical potential of PLCζ.

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.

Analysis of balanced reciprocal translocations in patients with subfertility using single-molecule optical mapping

PURPOSE

Approximately 1% of individuals who carry a balanced reciprocal translocation (BRT) are subfertile. Current karyotyping does not have the resolution to determine whether the breakpoints of the involved chromosomes perturb genes important for fertility. The aim of this study was to apply single-molecule optical mapping (SMOM) to patients presenting for IVF (in vitro fertilization) to ascertain whether the BRT disrupted any genes associated with normal fertility.

METHODS

Nine subfertile patients with different BRTs were recruited for the study. Methyltransferase enzyme DLE1 was used to fluorescently label their genomic DNA samples at the recognition motif CTTAAG. The SMOM was performed on the Bionano platform, and long molecules aligned against the reference genome hg19 to identify the breakpoint regions. Mate-pair and PCR-Sanger sequencing were used to confirm the precise breakpoint sequences.

RESULTS

Both breakpoint regions in each of the nine BRTs were finely mapped to small regions of approximately 10 Kb, and their positions were consistent with original cytogenetic banding patterns determined by karyotyping. In three BRTs, breakpoints disrupted genes known to be associated with male infertility, namely NUP155 and FNDC3A [46,XY,t(5;13)(p15;q22)], DPY19L1 [46,XY,t(1;7)(p36.3;p15), and BAI3 [46,XY,t(3;6)(p21;q16)].

CONCLUSIONS

The SMOM has potential clinical application as a rapid tool to screen patients with BRTs for underlying genetic causes of infertility and other diseases.

Reproductive outcomes of 3 infertile males with XYY syndrome: Retrospective case series and literature review

The aim of this study is to evaluate the pregnancy outcomes of males with a 47, XYY karyotype following assisted reproductive treatment.A retrospective study was performed using data from infertile men with 47, XYY at a center for reproductive medicine in 2004 to 2017. Of the 19,842 infertile males treated, a total of 21 showed the 47, XYY karyotype and were included in the present study. Clinical variables were collected. Three men were under treatment with their partner before either in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).The incidence of 47, XYY in infertile men is 1/945 (21/19842). Most men are azoospermic or severely oligospermic. Three men and their partners underwent IVF or ICSI treatment with fresh ejaculate samples. The fertilization rate was 52.94% to 83.33%. The embryo cleavage rate was 50% to 90%. One man had abnormal sex hormonal levels and his partner had no clinical pregnancy. The other 2 couples had healthy baby boys.Live spermatozoa can be gathered and fertility is possible for infertile males with 47, XYY syndrome when IVF or ICSI treatment is used. It is recommended that genetic counseling is provided in such cases.

Essential Role of Sperm-Specific PLC-Zeta in Egg Activation and Male Factor Infertility: An Update

Sperm-specific phospholipase C zeta (PLCζ) is widely considered to be the physiological stimulus responsible for generating calcium (Ca²⁺) oscillations that induce egg activation and early embryonic development during mammalian fertilization. In the mammalian testis, PLCζ expression is detected at spermiogenesis following elongated spermatid differentiation. Sperm-delivered PLCζ induces Ca²⁺ release via the inositol 1,4,5-trisphosphate (InsP₃) signaling pathway. PLCζ is the smallest known mammalian PLC isoform identified to date, with the simplest domain organization. However, the distinctive biochemical properties of PLCζ compared with other PLC isoforms contribute to its unique potency in stimulating cytosolic Ca²⁺ oscillations within mammalian eggs. Moreover, studies describing PLCζ “knockout” mouse phenotypes confirm the supreme importance of PLCζ at egg activation and monospermic fertilization in mice. Importantly, a number of clinical reports have highlighted the crucial importance of PLCζ in human fertilization by associating PLCζ deficiencies with certain forms of male factor infertility. Herein, we give an update on recent advances that have refined our understanding of how sperm PLCζ triggers Ca^{2 +} oscillations and egg activation in mammals, while also discussing the nature of a potential “alternative” sperm factor. We summarise PLCζ localization in mammalian sperm, and the direct links observed between defective PLCζ protein in sperm and documented cases of male infertility. Finally, we postulate how this sperm protein can be used as a potential diagnostic marker, and also as a powerful therapeutic agent for treatment of certain types of male infertility due to egg activation failure or even in more general cases of male subfertility.

The second mutation of SYCE1 gene associated with autosomal recessive nonobstructive azoospermia

PURPOSE

It is estimated that 40-50% of infertility among human couples is due to male infertility. Azoospermia is estimated to occur in 1% of all men and to be the cause of 10-20% of male infertility. Genetic defects, including single gene effects, maybe cause of azoospermia in 20-30% of affected males. Here, we aim to identify the genetic cause of azoospermia in a man who is also affected by hereditary spastic paraplegia.

METHODS

The proband was subjected to whole-exome sequencing, followed by a comprehensive in silico analysis to identify the azoospermia causative gene.

RESULTS

A novel splice site mutation c.375-2A > G in SYCE1 that is thought to be the cause of azoospermia was identified. This variant co-segregated with azoospermia status in the family that has three additional affected males.

CONCLUSION

SYCE1 gene encodes synaptonemal complex (SC) central element 1 protein which contributes to the formation of the synaptonemal complex during meiosis. Syce1 null male and female mice have been shown to be infertile. There have only been two reports on the effects of SYCE1 mutations in humans; it was shown as the cause of primary ovarian failure (POI) in one and as the cause of nonobstructive azoospermia (NOA) in another. We suggest that the mutation 375-2A > G, which affects the acceptor splice site within intron 6 of SYCE1, is the likely cause of azoospermia and subsequent infertility in the family studied. The finding constitutes the third report of SYCE1mutations that affect infertility in humans and further supports its contribution to this condition.

The Role of Number of Copies, Structure, Behavior and Copy Number Variations (CNV) of the Y Chromosome in Male Infertility

The World Health Organization (WHO) defines infertility as the inability of a sexually active, non-contracepting couple to achieve spontaneous pregnancy within one year. Statistics show that the two sexes are equally at risk. Several causes may be responsible for male infertility; however, in 30–40% of cases a diagnosis of idiopathic male infertility is made in men with normal urogenital anatomy, no history of familial fertility-related diseases and a normal panel of values as for endocrine, genetic and biochemical markers. Idiopathic male infertility may be the result of gene/environment interactions, genetic and epigenetic abnormalities. Numerical and structural anomalies of the Y chromosome represent a minor yet significant proportion and are the topic discussed in this review. We searched the PubMed database and major search engines for reports about Y-linked male infertility. We present cases of Y-linked male infertility in terms of (i) anomalies of the Y chromosome structure/number; (ii) Y chromosome misbehavior in a normal genetic background; (iii) Y chromosome copy number variations (CNVs). We discuss possible explanations of male infertility caused by mutations, lower or higher number of copies of otherwise wild type, Y-linked sequences. Despite Y chromosome structural anomalies are not a major cause of male infertility, in case of negative results and of normal DNA sequencing of the ascertained genes causing infertility and mapping on this chromosome, we recommend an analysis of the karyotype integrity in all cases of idiopathic fertility impairment, with an emphasis on the structure and number of this chromosome.

Screening of triploid with low-coverage whole-genome sequencing by a single-nucleotide polymorphism-based test in miscarriage tissue

PURPOSE

To establish a single-nucleotide polymorphism-based analysis (SBA) method to identify triploidy in the miscarriage tissue by using low-coverage whole-genome sequencing (LC-WGS).

METHODS

The method was established by fitting a quadratic curve model by counting the distribution of three heterozygous mutation content intervals. The triploid test result was mainly determined by the opening direction and the axis of symmetry of the quadratic curve, and Z test between the same batch samples was also used for auxiliary judgment.

RESULTS

Two hundred thirteen diploid samples and 8 triploid samples were used for establishment of the analytical method and 203 unknown samples were used for blind testing. In the blind testing, we found 2 cases positive for triploidy. After chromosome microarray analysis (CMA) and mass spectrometry verification, we found that both samples were true positives. We randomly selected 5 samples from the negative samples for mass spectrometry verification, and the results showed that these samples were all true negatives.

CONCLUSIONS

Our method achieved accurate detection of triploidy in the miscarriage tissue and has the potential to detect more chromosomal abnormality types such as uniparental disomy (UPD) using a single LC-WGS approach.

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.

Where are we going with gene screening for male infertility?

Male infertility is a heterogenous disease process requiring the proper functioning and interaction of thousands of genes. Given the number of genes involved, it is thought that genetic causes contribute to most cases of infertility. Identifying these causes, however, is challenging. Infertility is associated with negative health outcomes, such as cancer, highlighting the need to further understand the genetic underpinnings of this condition. This paper describes the genetic and genomic tests currently available to identify the etiology of male infertility and then will discuss emerging technologies that may facilitate diagnosis and treatment of in the future.

Chromosomal instability and pro-inflammatory response in aging

Aging refers to the progressive deterioration of tissue and organ function over time. Increasing evidence points to the accumulation of highly damaged cell cycle-arrested cells with age (cellular senescence) as major reason for the development of certain aging-associated diseases. Recent studies have independently shown that aneuploidy, an abnormal chromosome set, occurs in senescent cells, and that the accumulation of cytoplasmic DNA driven by faulty chromosome segregation during mitosis aids in the establishment of senescence and its associated secretory phenotype known as SASP. Here we review the emerging link between chromosomal instability (CIN) and senescence in the context of aging, with emphasis on the cGAS-STING pathway activation and its role in the development of the SASP. Based on current evidence, we propose that age-associated CIN in mitotically active cells contributes to aging and its associated diseases, and we discuss the inhibition of CIN as a potential strategy to prevent the generation of aneuploid senescent cells and thereby to delay aging.

Non-Robertsonian translocations involving chromosomes 13, 14, or 15 in male infertility: 28 cases and a review of the literature

For genetic counseling of male carriers of chromosomal translocations, the specific chromosomes and breakpoints involved in the translocation are relevant to know. The structural chromosomal abnormalities may lead to abnormal sperm counts, infertility, and miscarriage. These are related to the specific chromosomes and breakpoints involved in the translocation. To date, over 200 cases of non-Robertsonian translocation in male carriers have been described that involve chromosomes 13, 14, or 15.This study reports of 28 male carriers from our clinic with balanced reciprocal translocations of chromosome 13, 14, or 15, and a literature review of 201 cases. The 28 male carriers from our clinic were diagnosed by cytogenetic analyses: 19 subjects suffered from pregestational infertility and 9 from gestational infertility. The most common translocations were t(7;13), t(10;14), and t(3;15), observed respectively in 13 (46%), 8 (29%), and 8 (29%) of our subjects. The literature cases (n = 201) involved chromosome 13 (n = 83, 41%), chromosome 14 (n = 56, 28%) or 15 (n = 62, 31%) in which 75 breakpoints were identified, the most common breakpoint, 13q22, was observed in 12 subjects (6%), followed by 14q32 (n = 11), 15q15 (n = 9), and 15q22 (n = 9). Most breakpoints were related to gestational infertility, while breakpoints at 13p13, 13p12, 13p11.2, 13p11, 13q11, 13q15, 14p12, 14p10, 15p13, 15p10, and 15q22.2 were associated with pregestational infertility.Carriers of non-Robertsonian translocations involving chromosome 13, 14, or 15 and experiencing infertility should receive counseling with regard to chromosomal breakpoints as there seem to be consequences for treatment. Intracytoplasmic sperm injection with preimplantation genetic diagnosis (PGD) for the carriers with oligozoospermia, microscopic testicular sperm extraction or sperm from the sperm bank for the carriers with azoospermia should be considered for pregestational infertility. The carriers with gestational infertility can choose PGD or prenatal diagnosis.

Revisiting aneuploidy profile of surgically retrieved spermatozoa by whole exome sequencing molecular karyotype

Previous studies, including our own, have reported that spermatozoa isolated from the testis have remarkably higher occurrence of aneuploidy once isolated from azoospermic men. This notion, however, did not translate into a lower pregnancy rate nor a greater proportion of miscarriages. Indeed, ICSI offspring generated from surgically retrieved gametes did not suffer from increased karyotypic aneuploidy than children generated from ejaculated specimens. In recent years, aneuploidy assessments on a larger number of cells and utilizing more chromosome probes have reported a progressive decrease in chromosomal aberrations in spermatozoa directly retrieved from the seminiferous tubules. In light of the availability of more accurate molecular genetic techniques, we have decided to challenge the notion that sampling epididymal and testicular tissues yields spermatozoa with higher incidence of aneuploidy than those retrieved in the ejaculate. In a retrospective manner, we have carried out an analysis by FISH with 9 chromosome probes on at least 1000 cells from the ejaculates of 87 consenting men and the specimens of 6 azoospermic men, while spermatozoa of fertile donors were used as control. Aneuploidy by FISH yielded 0.9% for the donor control but rose in the study group to 3.6% in the ejaculated, 1.2% for the epididymal, and 1.1% for testicular spermatozoa. There were no differences in autosomal or gonosomal disomies, nor nullisomies. In this group, once the specimens of these men were used for ICSI, ejaculated spermatozoa yielded a 22% clinical pregnancy rate that resulted in 62.5% pregnancy loss. The surgically retrieved specimens yielded a 50% clinical pregnancy rate that progressed to term. To confirm our findings, in a prospective analysis, DNA sequencing was carried out on the ejaculates and surgical samples of 22 men with various spermatogenic characteristics. In this comparison, the findings were similar with actually a higher incidence of aneuploidy in the ejaculated spermatozoa (n = 16) compared to those surgically retrieved (n = 6) (P<0.0001). For this group, the clinical pregnancy rate for the ejaculated specimens was 47.2% with 29.4% pregnancy loss, while the surgically retrieved yielded a 50% clinical pregnancy rate, all progressing to term. A subsequent prospective combined assessment on ejaculated and surgically retrieved spermatozoa by FISH and NGS was performed on non-azoospermic men with high DNA fragmentation in their ejaculate. The assessment by FISH evidenced 2.8% chromosomal defects in the ejaculated and 1.2% in testicular biopsies while by NGS became 8.4% and 1.3% (P = 0.02), respectively. Interestingly, we evidenced a pregnancy rate of 0% with ejaculated while 100% with the testicular spermatozoa in this latter group. This indicates that improved techniques for assessing sperm aneuploidy on a wider number of cells disproves earlier reports and corroborates the safe utilization of testicular spermatozoa with a positive impact on chances of pregnancy.

Male infertility: establishing sperm aneuploidy thresholds in the laboratory

PURPOSE

Fluorescence in situ hybridization (FISH) in spermatozoa provides an estimate of the frequency of chromosomal abnormalities, but there is not a clinical consensus on how to statistically analyze sperm FISH results. We therefore propose a statistical approach to establish sperm aneuploidy thresholds in a fertile population.

METHODS

We have determined the distribution and variation of the frequency of nullisomy, disomy, and diploidy for a set of 13 chromosomes (1, 2, 9, 13, 15, 16, 17, 18, 19, 21, 22, X, and Y) in sperm nuclei from 14 fertile men by means of automatized FISH. The dispersion of data has been analyzed by the non-parametric Wilcoxon Rank Sum test. We have established the threshold values for each chromosome and aneuploidy type on the basis of the confidence interval values (99.9%).

RESULTS

Nullisomy thresholds ranged from 0.49% for chromosome 19 to 3.09% for chromosome 22; disomy thresholds ranged from 0.30% for chromosome 21 to 1.47% for chromosome 15; diploidy thresholds ranged from 0.24% for the 9/19 chromosome set to 1.21% for the 13/21 chromosome set.

CONCLUSIONS

Applying this approach with clinical purposes will enable us to categorize the patient as altered or normal regarding his sperm aneuploidy. Any result surpassing the cited threshold values indicates a 99.9% probability of being significantly different from fertile controls.

Association of Sperm Aneuploidy Frequency and DNA Fragmentation Index in Infertile Men

BACKGROUND

For improving the evaluation of male infertility, many parameters were studied and reported in earlier literature. The aim of this study was to estimate the frequency of sperm aneuploidy and DNA fragmentation in infertile men and to assess the correlation between sperm aneuploidy and DNA fragmentation.

METHODS

In this study 100 infertile men were included, cases with azoospermia were 68%, oligospermia 18%, severe oligospermia 6%, and oligoasthenoteratospermia (OAT) 8%. Ten normozoospermic men who had two normal children were included as a control. The sperm aneuploidy test by Fluorescence In Situ Hybridization (FISH) and sperm DNA fragmentation index by TdT (Terminal deoxynucleotidyl transferase)-mediated dUTP nick end labelling (TUNEL) were carried out. To determine the aneuploidy status and DNA fragmentation index, frequency was used. The correlation between sperm aneuploidy and sperm DNA fragmentation along with age was assessed by using Spearman's correlation coefficient. The p<0.05 was considered significant.

RESULTS

The age of 100 subjects ranged between 22-48 years (35.5±5.1). Sperm aneuploidy frequency and DNA fragmentation rate were found to be higher in infertile men compared to control men (n=10). There was a significant relationship between age and sex chromosomal aneuploidy (p<0.05) and significant difference between sperm aneuploidy and damaged DNA (p<0.05).

CONCLUSION

FISH and TUNEL assay results showed increased sperm aneuploidy frequency, and DNA fragmentation index in infertile men compared with the fertile men. There is significant relationship observed between sperm aneuploidy and DNA fragmentation. These two parameters are important and they must be investigated for clinical practice.