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Nonobstructive azoospermia (NOA), the most severe manifestation of male infertility, lacks a comprehensive understanding of its genetic etiology. Here, a bi-allelic loss-of-function variant in REC114 (c.568C > T: p.Gln190*) were identified through whole exome sequencing (WES) in a Chinese NOA patient. Testicular histopathological analysis and meiotic chromosomal spread analysis were conducted to assess the stage of spermatogenesis arrested. Co-immunoprecipitation (Co-IP) and Western blot (WB) were used to investigate the influence of variant in vitro. In addition, our results revealed that the variant resulted in truncated REC114 protein and impaired interaction with MEI4, which was essential for meiotic DNA double-strand break (DSB) formation. As far as we know, this study presents the first report that identifies REC114 as the causative gene for male infertility. Furthermore, our study demonstrated indispensability of the REC114-MEI4 complex in maintaining DSB homoeostasis, and highlighted that the disruption of the complex due to the REC114 variant may underline the mechanism of NOA., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Genetic causation for the majority of non-obstructive azoospermia (NOA) remains unclear. Mutations in synaptonemal complex (SC)-associated genes could cause meiotic arrest and NOA. Previous studies showed that heterozygous truncating variants in SYCP2 encoding a protein essential for SC formation, are associated with non-obstructive azoospermia and severe oligozoospermia. Herein, we showed a homozygous loss-of-function variant in SYCP2 (c.2689_2690insT) in an NOA-affected patient. And this variant was inherited from heterozygous parental carriers by natural reproduction. HE, IF, and meiotic chromosomal spread analyses demonstrated that spermatogenesis was arrested at the zygotene stage in the proband with NOA. Thus, this study revealed that SYCP2 associated with NOA segregates in an autosomal recessive inheritance pattern, rather than an autosomal dominant pattern. Furthermore, our study expanded the knowledge of variants in SYCP2 and provided new insight into understanding the genetic etiology of NOA., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Non-obstructive azoospermia (NOA) is characterized by the failure of sperm production due to testicular disorders and represents the most severe form of male infertility. Growing evidences have indicated that gene defects could be the potential cause of NOA via genome-wide sequencing approaches. Here, bi-allelic deleterious variants in meiosis inhibitor protein 1 (MEI1) were identified by whole-exome sequencing in four Chinese patients with NOA. Testicular pathologic analysis and immunohistochemical staining revealed that spermatogenesis is arrested at spermatocyte stage, with defective programmed DNA double-strand breaks (DSBs) homoeostasis and meiotic chromosome synapsis in patients carrying the variants. In addition, our results showed that one missense variant (c.G186C) reduced the expression of MEI1 and one frameshift variant (c.251delT) led to truncated proteins of MEI1 in in vitro. Furthermore, the missense variant (c.T1585A) was assumed to affect the interaction between MEI1 and its partners via bioinformatic analysis. Collectively, our findings provide direct genetic and functional evidences that bi-allelic variants in MEI1 could cause defective DSBs homoeostasis and meiotic chromosome synapsis, which subsequently lead to meiosis arrest and male infertility. Thus, our study deepens our knowledge of the role of MEI1 in male fertility and provides a novel insight to understand the genetic aetiology of NOA., (© 2023. The Author(s), under exclusive licence to The Japan Society of Human Genetics.)

Background: Non-obstructive azoospermia (NOA) is the most severe disease in male infertility, but the genetic causes for majority of NOA remain unknown., Methods: Two Chinese NOA-affected patients were recruited to identify the genetic causal factor of infertility. Whole-exome sequencing (WES) was conducted in the two patients with NOA. Sanger sequencing and CNV array were used to ascertain the WES results. Hematoxylin and eosin (H&E) staining and immunofluorescence (IF) were carried out to evaluate the stage of spermatogenesis arrested in the affected cases., Results: Novel heterozygous deletion (LOH) within SYCE1 (seq[GRCh37] del(10)(10q26.3)chr10:g.135111754_135427143del) and heterozygous loss of function (LoF) variant in SYCE1 (NM_001143763: c.689_690 del:p.F230fs) were identified in one NOA-affected patient. While homozygous deletion within SYCE1 (seq[GRCh37] del(10)(10q26.3)chr10:g.135340247_135379115del) was detected in the other patient with meiotic arrest. H&E and IF staining demonstrated that the spermatogenesis was arrested at pachytene stage in the two patients with NOA, suggesting these two novel CNVs within SYCE1 could lead to meiotic defect and NOA., Conclusions: We identified that two novel CNVs within SYCE1 are associated with meiotic arrest and male infertility. Thus, our study expands the knowledge of variants in SYCE1 and provides a new insight to understand the genetic etiologies of NOA., (© 2022. The Author(s).)

The genetic causes of idiopathic premature ovarian insufficiency (POI) and nonobstructive azoospermia (NOA) remain unclear. We performed whole-exome sequencing (WES) in members of a consanguineous family with two POI and two NOA patients to screen for potential pathogenic variants for familial POI and NOA. And a homozygous variant in SPATA22 (c.400C>T:p.R134X) was identified. Histological analysis and spermatocyte spreading assay demonstrated that the spermatogenesis was arrested at a zygotene-like stage in the proband with NOA. The candidate gene was further screened in the in-house WES database of idiopathic POI-affected patients. One additional compound heterozygous variant in SPATA22 (c.900+1G>A and c.31C>T:p.R11X) was found in one patient with sporadic POI and validated by minigene assay. Thus, this is the first report identifying SPATA22 as the causative gene for human POI. Combined with the observations in the familial patient with NOA, our findings highlighted the essential role of meiotic HR genes in gametogenesis and gonadal function maintenance., (© 2022 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.)

This study aimed to evaluate the efficacy and safety of vasal vessel-sparing modified single-armed 2-suture longitudinal intussusception vasoepididymostomy (SA-LIVE) to epididymal obstructive azoospermia patients. Forty consecutive epididymal obstructive azoospermia cases, who underwent microsurgical vasoepididymostomy in Shanghai General Hospital from January 2019 to October 2019, were included in this study. Twenty cases underwent SA-LIVE (group A), and 20 cases underwent vasal vessel-sparing SA-LIVE (group B). Until March 2021, the mean follow-up period was 16.9 ± 4.1 (12-23) months. The overall patency rate was 82.5%, and 80% and 85% for group A and group B respectively. The mean time to achieve patency was 4.11 ± 2.74 months. The overall natural pregnancy rate was 51.5%(17/33) at the mean follow-up of 16.9 months. The natural pregnancy rate was 50.0% for group A and 52.9% for group B (p > .05). At the time of 6 months post-operation, the patency rate was 70% for group A and 80% for group B (p = .465); the natural pregnancy rate was 0% for group A and 31.3% for group B (p = .022). Vasal vessel-sparing SA-LIVE is safe and effective to achieve favourable patency and pregnancy rates. Preserving vasal vessel would improve natural pregnancy rate at a very early stage., (© 2021 Wiley-VCH GmbH.)

Primate‐specific DAZ (deleted in azoospermia) has evolved in the azoospermia factor c (AZFc) locus on the Y chromosome. Loss of DAZ is associated with azoospermia in patients with deletion of the AZFc region (AZFc_del). However, the molecular mechanisms of DAZ in spermatogenesis remain uncertain. In this study, the molecular mechanism of DAZ is identified, which is unknown since it is identified 40 years ago because of the lack of a suitable model. Using clinical samples and cell models, it is shown that DAZ plays an important role in spermatogenesis and that loss of DAZ is associated with defective proliferation of c‐KIT‐positive spermatogonia in patients with AZFc_del. Mechanistically, it is shown that knockdown of DAZ significantly downregulated global translation and subsequently decreased cell proliferation. Furthermore, DAZ interacted with PABPC1 via the DAZ repeat domain to regulate global translation. DAZ targeted mRNAs that are involved in cell proliferation and cell cycle phase transition. These findings indicate that DAZ is a master translational regulator and essential for the maintenance of spermatogonia. Loss of DAZ may result in defective proliferation of c‐KIT‐positive spermatogonia and spermatogenic failure. [ABSTRACT FROM AUTHOR]

Background Objectives Materials and methods Results Conclusion Pediatric inguinal hernia repair (IHR) is a common cause of obstructive azoospermia (OA). Yet, the surgical treatment for this kind of OA remains difficult with poor fertility outcome.To evaluate the safety and effectiveness of totally extraperitoneal laparoscopy‐assisted microsurgical vasovasostomy (VV) in the treatment of OA caused by pediatric bilateral IHR.Totally, 37 patients with OA caused by pediatric bilateral IHR were enrolled in this study from March 2015 to December 2020 in Shanghai General Hospital. The clinical data and fertility outcomes were collected and analyzed.All patients enrolled had a history of bilateral IHR at the age of 1–10 years old. The mean age of patients was 27 ± 4.31 (range: 18–35) years. Totally extraperitoneal laparoscopy (TEP) was applied in 31 patients for the exploration and retrieval of pelvic vas deferens end, and 30 of them underwent microsurgical VV successfully. Among the six cases where TEP was not applied, five cases underwent microsurgical anastomosis. Intraoperative exploration revealed that the location of vas deferens injuries included scrotum (2.70%, 1/37), inguinal canal (5.41%, 2/37), pelvic cavity (78.37%, 29/37), and multiple sites (13.51%, 5/37). The mean operation time was 339 ± 96.73 min (range: 130–510 min). There were no surgical complications. Thirty‐three cases were followed up for 5–48 months with four cases lost to follow‐up. The overall patency rate, pregnancy rate, and natural pregnancy rate were 75.86% (22/29), 46.67% (14/30), and 36.84% (7/19, 3 patients without family planning), respectively. And seven couples conceived through the assisted reproductive technique, two of which using fresh sperm in the ejaculate.TEP laparoscopy‐assisted microscopic VV is an effective treatment for patients with OA caused by pediatric bilateral IHR. [ABSTRACT FROM AUTHOR]

Background. Aromatase inhibitors (AIs) can significantly improve semen parameters in infertile men. In this study, we investigated the efficacy of AIs for azoospermia in a Chinese population with AZFc microdeletion. Aims. Patients with AZFc microdeletion who were treated with AIs were analyzed retrospectively by collecting clinical data, including their hormone profile and treatment outcome. Patients were divided into those with sperm in their semen after AI treatment (group A) and those without sperm in their semen after AI treatment (group B). Results. The rate of Y chromosome AZF microdeletions was 9.30% (313/3364) from March 2015 to March 2021, among which patients with complete AZFc microdeletion accounted for 63.2% (198/313), and of the 198 patients with AZFc microdeletion, 69.7% (138/198) showed azoospermia. Forty-six (33.3%) of the azoospermic patients had sperm in their semen after AI administration. Testosterone (T) and testosterone-to-estradiol ratio (T/E2) levels were higher in group A than those in group B after treatment, and the differences were significant (T, P = 0.038 ; T/E2, P = 0.004). Paired t -test demonstrated that the change of T levels before and after treatment was statistically significant (P = 0.003). The increased E2 and T/E2 ratio levels before and after treatment were not statistically significant (P = 0.057 and 0.080), but they were close to the threshold value (P = 0.05). Conclusions. Patients with AZFc microdeletion accounted for the largest proportion of male infertility caused by Y chromosome microdeletions. AIs can promote spermatogenesis in azoospermic patients with AZFc microdeletion, and sperm could be found in the semen of some patients after AI administration. T and T/E2 levels after AI treatment could be used as biomarkers to distinguish azoospermic patients with AZFc microdeletion who responded better to AIs from those who did not respond well. [ABSTRACT FROM AUTHOR]