Search

STUDY QUESTION What is the load, distribution and added clinical value of secondary findings (SFs) identified in exome sequencing (ES) of patients with non-obstructive azoospermia (NOA)? SUMMARY ANSWER One in 28 NOA cases carried an identifiable, medically actionable SF. WHAT IS KNOWN ALREADY In addition to molecular diagnostics, ES allows assessment of clinically actionable disease-related gene variants that are not connected to the patient’s primary diagnosis, but the knowledge of which may allow the prevention, delay or amelioration of late-onset monogenic conditions. Data on SFs in specific clinical patient groups, including reproductive failure, are currently limited. STUDY DESIGN, SIZE, DURATION The study group was a retrospective cohort of patients with NOA recruited in 10 clinics across six countries and formed in the framework of the international GEMINI (The GEnetics of Male INfertility Initiative) study. PARTICIPANTS/MATERIALS, SETTING, METHODS ES data of 836 patients with NOA were exploited to analyze SFs in 85 genes recommended by the American College of Medical Genetics and Genomics (ACMG), Geisinger’s MyCode, and Clinical Genome Resource. The identified 6374 exonic variants were annotated with ANNOVAR and filtered for allele frequency, retaining 1381 rare or novel missense and loss-of-function variants. After automatic assessment of pathogenicity with ClinVar and InterVar, 87 variants were manually curated. The final list of confident disease-causing SFs was communicated to the corresponding GEMINI centers. When patient consent had been given, available family health history and non-andrological medical data were retrospectively assessed. MAIN RESULTS AND THE ROLE OF CHANCE We found a 3.6% total frequency of SFs, 3.3% from the 59 ACMG SF v2.0 genes. One in 70 patients carried SFs in genes linked to familial cancer syndromes, whereas 1 in 60 cases was predisposed to congenital heart disease or other cardiovascular conditions. Retrospective assessment confirmed clinico-molecular diagnoses in several cases. Notably, 37% (11/30) of patients with SFs carried variants in genes linked to male infertility in mice, suggesting that some SFs may have a co-contributing role in spermatogenic impairment. Further studies are needed to determine whether these observations represent chance findings or the profile of SFs in NOA patients is indeed different from the general population. LIMITATIONS, REASONS FOR CAUTION One limitation of our cohort was the low proportion of non-Caucasian ethnicities (9%). Additionally, as comprehensive clinical data were not available retrospectively for all men with SFs, we were not able to confirm a clinico-molecular diagnosis and assess the penetrance of the specific variants. WIDER IMPLICATIONS OF THE FINDINGS For the first time, this study analyzed medically actionable SFs in men with spermatogenic failure. With the evolving process to incorporate ES into routine andrology practice for molecular diagnostic purposes, additional assessment of SFs can inform about future significant health concerns for infertility patients. Timely detection of SFs and respective genetic counseling will broaden options for disease prevention and early treatment, as well as inform choices and opportunities regarding family planning. A notable fraction of SFs was detected in genes implicated in maintaining genome integrity, essential in both mitosis and meiosis. Thus, potential genetic pleiotropy may exist between certain adult-onset monogenic diseases and NOA. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Estonian Research Council grants IUT34-12 and PRG1021 (M.L. and M.P.); National Institutes of Health of the United States of America grant R01HD078641 (D.F.C., K.I.A. and P.N.S.); National Institutes of Health of the United States of America grant P50HD096723 (D.F.C. and P.N.S.); National Health and Medical Research Council of Australia grant APP1120356 (M.K.O’B., D.F.C. and K.I.A.); Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Inovação grant POCI-01-0145-FEDER-007274 (A.M.L., F.C. and J.G.) and FCT: IF/01262/2014 (A.M.L.). J.G. was partially funded by FCT/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES), through the Centre for Toxicogenomics and Human Health—ToxOmics (grants UID/BIM/00009/2016 and UIDB/00009/2020). M.L.E. is a consultant for, and holds stock in, Roman, Sandstone, Dadi, Hannah, Underdog and has received funding from NIH/NICHD. Co-authors L.K., K.L., L.N., K.I.A., P.N.S., J.G., F.C., D.M.-M., K.A., K.A.J., M.K.O’B., A.M.L., D.F.C., M.P. and M.L. declare no conflict of interest. TRIAL REGISTRATION NUMBER N/A.

De novo mutations are known to play a prominent role in sporadic disorders with reduced fitness. We hypothesize that de novo mutations play an important role in severe male infertility and explain a portion of the genetic causes of this understudied disorder. To test this hypothesis, we utilize trio-based exome sequencing in a cohort of 185 infertile males and their unaffected parents. Following a systematic analysis, 29 of 145 rare (MAF, Germline de novo mutations can impact individual fitness, but their role in human male infertility is understudied. Trio-based exome sequencing identifies many new candidate genes affecting male fertility, including an essential regulator of male germ cell pre-mRNA splicing.

Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8266742/pdf/nihms-1705620.pdf GEMINI Consortium: Donald F Conrad, Liina Nagirnaja, Kenneth I Aston, Douglas T Carrell, James M Hotaling, Timothy G Jenkins, Rob McLachlan, Moira K O'Bryan, Peter N Schlegel, Michael L Eisenberg, Jay I Sandlow, Emily S Jungheim, Kenan R Omurtag, Alexandra M Lopes, Susana Seixas, Filipa Carvalho, Susana Fernandes, Alberto Barros, João Gonçalves, Iris Caetano, Graça Pinto, Sónia Correia, Maris Laan, Margus Punab, Ewa Rajpert-De Meyts, Niels Jørgensen, Kristian Almstrup, Csilla G Krausz, Keith A Jarvi. Member of GEMINI Consortium: João Gonçalves (INSA), lista completa na pág 1179. Male infertility impacts millions of couples yet, the etiology of primary infertility remains largely unknown. A critical element of successful spermatogenesis is maintenance of genome integrity. Here, we present a genomic study of spermatogenic failure (SPGF). Our initial analysis (n=176) did not reveal known gene-candidates but identifed a potentially signifcant single-nucleotide variant (SNV) in X-linked germ-cell nuclear antigen (GCNA). Together with a larger follow-up study (n=2049), 7 likely clinically relevant GCNA variants were identifed. GCNA is critical for genome integrity in male meiosis and knockout models exhibit impaired spermatogenesis and infertility. Single-cell RNA-seq and immunohistochemistry confrm human GCNA expression from spermatogonia to elongated spermatids. Five identifed SNVs were located in key functional regions, including N-terminal SUMO-interacting motif and C-terminal Spartan-like protease domain. Notably, variant p.Ala115ProfsTer7 results in an early frameshift, while Spartan-like domain missense variants p.Ser659Trp and p.Arg664Cys change conserved residues, likely afecting 3D structure. For variants within GCNA’s intrinsically disordered region, we performed computational modeling for consensus motifs. Two SNVs were predicted to impact the structure of these consensus motifs. All identifed variants have an extremely low minor allele frequency in the general population and 6 of 7 were not detected in>5000 biological fathers. Considering evidence from animal models, germ-cell-specifc expression, 3D modeling, and computational predictions for SNVs, we propose that identifed GCNA variants disrupt structure and function of the respective protein domains, ultimately arresting germ-cell division. To our knowledge, this is the frst study implicating GCNA, a key genome integrity factor, in human male infertility. This study was supported by The Eunice Kennedy Shriver NICHD Grant HD080755 (ANY), the Magee-Womens Research Institute University of Pittsburgh Start Up Fund (ANY), PA DoH Grant SAP4100085736 (ANY), NIH P50 Specialized Center Grant HD096723 (KO, ANY, DC, PNS, KH, and MBE), German Research Foundation Clinical Research Unit ‘Male Germ Cells’ grant DFG CRU326 (FT), National Science Centre in Poland, grants no.: 2017/26/D/NZ5/00789 (AM) and 2015/17/B/NZ2/01157; NCN 2020/37/B/NZ5/00549 (MK), Magee-Womens Research Institute University of Pittsburgh, Faculty Fellowship Award and NICHD T32 HD087194 (JH), GM125812 (MB), GM127569 (MB, JLY, and ANY), NIH R00H090289 (MABE), National Health and Medical Research Council Project grant APP1120356 (MKOB, JAV, and DC), UUKi Rutherford Fund Fellowship (BJH), Estonian Research Council, grants IUT34-12 and PRG1021 (ML), and The Netherlands Organization for Scientifc Research grant no.: 918-15-667 as well as an Investigator Award in Science from the Wellcome Trust grant no.: 209451 (JAV). Computational analysis was supported in part by the University of Pittsburgh Center for Research Computing through the resources provided. info:eu-repo/semantics/publishedVersion

Male infertility affects ∼7% of men, but its causes remain poorly understood. The most severe form is non-obstructive azoospermia (NOA), which is, in part, caused by an arrest at meiosis. So far, only a few validated disease-associated genes have been reported. To address this gap, we performed whole-exome sequencing in 58 men with unexplained meiotic arrest and identified the same homozygous frameshift variant c.676dup (p.Trp226LeufsTer4) in M1AP, encoding meiosis 1 associated protein, in three unrelated men. This variant most likely results in a truncated protein as shown in vitro by heterologous expression of mutant M1AP. Next, we screened four large cohorts of infertile men and identified three additional individuals carrying homozygous c.676dup and three carrying combinations of this and other likely causal variants in M1AP. Moreover, a homozygous missense variant, c.1166C>T (p.Pro389Leu), segregated with infertility in five men from a consanguineous Turkish family. The common phenotype between all affected men was NOA, but occasionally spermatids and rarely a few spermatozoa in the semen were observed. A similar phenotype has been described for mice with disruption of M1ap. Collectively, these findings demonstrate that mutations in M1AP are a relatively frequent cause of autosomal recessive severe spermatogenic failure and male infertility with strong clinical validity. This work was carried out within the frame of the German Research Foundation Clinical Research Unit ‘‘Male Germ Cells: from Genes to Function’’ (DFG CRU326). Funding for sequencing of the GEMINI cohort was provided by the National Institutes of Health, United States (R01HD078641). The analyses in the Turkish family were supported by a grant from the Bursa University of Uludag Project Unit [KUAP(T)-2014/36]. info:eu-repo/semantics/publishedVersion

Dynein complexes are large, multi-unit assemblies involved in many biological processes including male fertility via their critical roles in protein transport and axoneme motility. Previously we identified a pathogenic variant in the dynein gene AXDND1 in an infertile man. Subsequently we identified an additional four potentially compound heterozygous variants of unknown significance in AXDND1 in two additional infertile men. We thus tested the role of AXDND1 in mammalian male fertility by generating a knockout mouse model. Axdnd1 -/- males were sterile at all ages but could undergo one round of histologically complete spermatogenesis. Subsequently, a progressive imbalance of spermatogonial commitment to spermatogenesis over self-renewal occurred, ultimately leading to catastrophic germ cell loss, loss of blood-testis barrier patency and immune cell infiltration. Sperm produced during the first wave of spermatogenesis were immotile due to abnormal axoneme structure, including the presence of ectopic vesicles and abnormalities in outer dense fibres and microtubule doublet structures. Sperm output was additionally compromised by a severe spermiation defect and abnormal sperm individualisation. Collectively, our data highlight the essential roles of AXDND1 as a regulator of spermatogonial commitment to spermatogenesis and during the processes of spermiogenesis where it is essential for sperm tail development, release and motility., Competing Interests: Conflicts of interest The authors have declared that no conflict of interest exists.