Browsing by Author "Wyrwoll, Margot J."
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- Bi-allelic Mutations in M1AP Are a Frequent Cause of Meiotic Arrest and Severely Impaired Spermatogenesis Leading to Male InfertilityPublication . Wyrwoll, Margot J.; Temel, Şehime G.; Nagirnaja, Liina; Oud, Manon S.; Lopes, Alexandra M.; van der Heijden, Godfried W.; Heald, James S.; Rotte, Nadja; Wistuba, Joachim; Wöste, Marius; Ledig, Susanne; Krenz, Henrike; Smits, Roos M.; Carvalho, Filipa; Gonçalves, João; Fietz, Daniela; Türkgenç, Burcu; Ergören, Mahmut C.; Çetinkaya, Murat; Başar, Murad; Kahraman, Semra; McEleny, Kevin; Xavier, Miguel J.; Turner, Helen; Pilatz, Adrian; Röpke, Albrecht; Dugas, Martin; Kliesch, Sabine; Neuhaus, Nina; Aston, Kenneth I.; Conrad, Donald F.; Veltman, Joris A.; Friedrich, Corinna; Tüttelmann, FrankMale 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.
- Disruption of human meiotic telomere complex genes TERB1, TERB2 and MAJIN in men with non-obstructive azoospermiaPublication . Salas-Huetos, Albert; Tüttelmann, Frank; Wyrwoll, Margot J.; Kliesch, Sabine; Lopes, Alexandra M.; Gonçalves, João; Boyden, Steven E.; Wöste, Marius; Hotaling, James M.; GEMINI Consortium; Nagirnaja, Liina; Conrad, Donald F.; Carrell, Douglas T.; Aston, Kenneth I.Non-obstructive azoospermia (NOA), the lack of spermatozoa in semen due to impaired spermatogenesis affects nearly 1% of men. In about half of cases, an underlying cause for NOA cannot be identified. This study aimed to identify novel variants associated with idiopathic NOA. We identified a nonconsanguineous family in which multiple sons displayed the NOA phenotype. We performed whole-exome sequencing in three affected brothers with NOA, their two unaffected brothers and their father, and identified compound heterozygous frameshift variants (one novel and one extremely rare) in Telomere Repeat Binding Bouquet Formation Protein 2 (TERB2) that segregated perfectly with NOA. TERB2 interacts with TERB1 and Membrane Anchored Junction Protein (MAJIN) to form the tripartite meiotic telomere complex (MTC), which has been shown in mouse models to be necessary for the completion of meiosis and both male and female fertility. Given our novel findings of TERB2 variants in NOA men, along with the integral role of the three MTC proteins in spermatogenesis, we subsequently explored exome sequence data from 1495 NOA men to investigate the role of MTC gene variants in spermatogenic impairment. Remarkably, we identified two NOA patients with likely damaging rare homozygous stop and missense variants in TERB1 and one NOA patient with a rare homozygous missense variant in MAJIN. Available testis histology data from three of the NOA patients indicate germ cell maturation arrest, consistent with mouse phenotypes. These findings suggest that variants in MTC genes may be an important cause of NOA in both consanguineous and outbred populations.
- Variants in GCNA, X-linked germ-cell genome integrity gene, identified in men with primary spermatogenic failurePublication . Hardy, Jimmaline J.; Wyrwoll, Margot J.; Mcfadden, William; Malcher, Agnieszka; Rotte, Nadja; Pollock, Nijole C.; Munyoki, Sarah; Veroli, Maria V.; Houston, Brendan J.; Xavier, Miguel J.; Kasak, Laura; Punab, Margus; Laan, Maris; Kliesch, Sabine; Schlegel, Peter; Jaffe, Thomas; Hwang, Kathleen; Vukina, Josip; Brieño-Enríquez, Miguel A.; Orwig, Kyle; Yanowitz, Judith; Buszczak, Michael; Veltman, Joris A.; Oud, Manon; Nagirnaja, Liina; Olszewska, Marta; O’Bryan, Moira K.; Conrad, Donald F.; Kurpisz, Maciej; Tüttelmann, Frank; Yatsenko, Alexander N.; Conrad, Donald F.; Nagirnaja, Liina; Aston, Kenneth I.; Carrell, Douglas T.; Hotaling, James M.; Jenkins, Timothy G.; McLachlan, Rob; O’Bryan, Moira K.; Schlegel, Peter N.; Eisenberg, Michael L.; Sandlow, Jay I.; Jungheim, Emily S.; Omurtag, Kenan R.; Lopes, Alexandra M.; Seixas, Susana; Carvalho, Filipa; Fernandes, Susana; Barros, Alberto; Gonçalves, João; Caetano, Iris; Pinto, Graça; Correia, Sónia; Laan, Maris; Punab, Margus; Meyts, Ewa Rajpert-De; Jørgensen, Niels; Almstrup, Kristian; Krausz, Csilla G.; Jarvi, Keith A.; on behalf of GEMINI ConsortiumMale 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.