Azoospermia and reciprocal translocations: should whole-exome sequencing be recommended?

Comprehensive analysis of chromosomal breakpoints and candidate genes associated with male infertility: insights from cytogenetic studies and expression analyses

The study aimed to investigate prevalent chromosomal breakpoints identified in balanced structural chromosomal anomalies and to pinpoint potential candidate genes linked with male infertility. This was acchieved through a comprehensive approach combining RNA-seq and microarray data analysis, enabling precise identification of candidate genes. The Cytogenetics data from 2,500 infertile males referred to Royan Research Institute between 2009 and 2022 were analyzed, with 391 cases meeting the inclusion criteria of balanced chromosomal rearrangement. Of these, 193 cases exhibited normal variations and were excluded from the analysis. By examining the breakpoints, potential candidate genes were suggested. Among the remaining 198 cases, reciprocal translocations were the most frequent anomaly (129 cases), followed by Robertsonian translocations (43 cases), inversions (34 cases), and insertions (3 cases).Some patients had more than one chromosomal abnormality. Chromosomal anomalies were most frequently observed in chromosomes 13 (21.1%), 14 (20.1%), and 1 (16.3%) with 13q12, 14q12, and 1p36.3 being the most prevalent breakpoints, respectively. Chromosome 1 contributed the most to reciprocal translocations (20.2%) and inversions (17.6%), while chromosome 14 was the most involved in the Robertsonian translocations (82.2%). The findings suggested that breakpoints at 1p36.3 and 14q12 might be associated with pregestational infertility, whereas breakpoints at 13q12 could be linked to both gestational and pregestational infertility. Several candidate genes located on common breakpoints were proposed as potentially involved in male infertility. Bioinformatics analyses utilizing three databases were conducted to examine the expression patterns of 78 candidate genes implicated in various causes of infertility.‏ In azoospermic individuals, significant differential expression was observed in 19 genes: 15 were downregulated (TSSK2, SPINK2, TSSK4, CDY1, CFAP70, BPY2, BTG4, FKBP6, PPP2R1B, SPECC1L, CENPJ, ‏SKA3, FGF9, NODAL, CLOCK), while four genes were upregulated ‏(‏HSPB1, MIF, PRF1, ENTPD6). In the case of Asthenozoospermia, seven genes showed significant upregulation (PRF1, DDX21, KIT, SRD5A3, MTCH1, DDX50, NODAL). Though RNA-seq data for Teratozoospermia were unavailable, microarray data revealed differential expression insix genes: three downregulated (BUB1, KLK4, PIWIL2) and three upregulated (AURKC, NPM2, RANBP2). These findings enhance our understanding of the molecular basis of male infertility and could provide valuable insights for future diagnostic and therapeutic strategies.

Comparative transcriptomics revealed the ecological trap effect of linearly polarized light on Oratosquilla oratoria

Although polarized light can assist many animals in performing special visual tasks, current polarized light pollution (PLP) caused by urban construction has been shown to induce maladaptive behaviors of PL-sensitive animals and change ecological interactions. However, the underlying mechanisms remain unclear. Our previous work hypothesized that linearly polarized light (LPL) is an ecological trap for Oratosquilla oratoria, a common Stomatopoda species in the China Sea. Here we explored the underlying negative effects of artificially LPL on O. oratoria based on comparative transcriptomics. We identified 3616 differentially expressed genes (DEGs) in O. oratoria compound eyes continuous exposed to natural light (NL) and LPL scenarios. In comparison with the NL scenario, a total of 1972 up- and 1644 down- regulated genes were obtained from the O. oratoria compound eyes under LPL scenario, respectively. Furthermore, we performed functional annotation of those DEGs described above and identified 65 DEGs related to phototransduction, reproduction, immunity, and synapse. Based on the functional information, we suspected that continuous LPL exposure could block the light transmission, disrupt the reproductive process, and lead to the progressive failure of the immune response of O. oratoria. In conclusion, this study is the first to systematically describe the negative effects of artificial LPL exposure on O. oratoria at the genetic level, and it can improve the biological conservation theory behind PLP.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Analysis of 2 men with t(8;22)(q13;q13) and t(8;14)(q13;q22) chromosomal translocation karyotypes

Male infertility is a multifactorial condition that is closely associated with chromosomal abnormalities. Reciprocal chromosomal translocation (RCT) is a significant structural genetic abnormality. The specific mechanisms of forms of RCT affecting male infertility include the product of chromosomally unbalanced gametes, thereby disrupting the structure and function of important genes responsible for spermatogenesis. RCT breakpoints have been found to disrupt gene structure and function in many medical fields However, the relationship between RCT breakpoints and male infertility remains to be determined. The purpose of this study is to describe 2 male carriers of RCTs 46,XY,t(8;22)(q13;q13) and 46,XY,t(8;14)(q13;q22). Both patients were collected from the second hospital of Jilin University. Semen parameters were detected using the computer-aided semen analysis system. Cytogenetic analysis was performed using standard operating procedure. Related genes on chromosomal breakpoints were searched using Online Mendelian Inheritance in Man. One man had semen parameters within the normal range, but the couple was infertile after 5 years of marriage. The other man showed normal semen parameters, and his wife had experienced 2 spontaneous miscarriages. Using a literature search, the association between chromosome 22q13 breakpoint and fertility were investigated. The results suggest that physicians should focus on the clinical phenotype of the patients and the breakpoints of RCT in genetic counseling. An important gene related to human male infertility is clearly located in chromosome region 22q13, and its function is worthy of further study.