Browsing by Author "Conrad, D.F."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Biallelic mutations in M1AP are associated with meiotic arrest, severely impaired spermatogenesis and male infertilityPublication . Friedrich, C.; Temel, S.G.; Nagirnaja, L.; Oud, M.S.; Lopes, A.M.; van der Heijden, G.W.; Heald, J.; Rotte, N.; Heald, J.; Rotte, N.; Wistuba, J.; Wöste, M.; Ledig, S.; Krenz, H.; Smits, R.M.; Carvalho, F.; Gonçalves, João; Fietz, D.; Türkgenç, B.; Ergören, M.C.; Çetinkaya, M.; Başar, M.; Kahraman, S.; McEleny, K.; Xavier, M.J.; Turner, H.; Pilatz, A.; Röpke, A.; Dugas, M.; Kliesch, S.; Neuhaus, N.; GEMINI Consortium; Aston, K.I.; Conrad, D.F.; Veltman, J.A.; Wyrwoll, M.J.; Tüttelmann, F.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, but so far only few validated causal genes have been reported. To address this gap, we performed whole exome sequencing in 58 men with unexplained meiotic arrest and identified in three unrelated men the same homozygous frameshift variant c.676dup (p.Trp226LeufsTer4) in M1AP, encoding meiosis 1 arresting protein. This variant results in a truncated protein lacking 57% of its full-length as shown in vitro by heterologous expression of mutated M1AP. Next, we screened four large cohorts of 1904 infertile men from the International Male Infertility Genomics Consortium (IMIGC) and identified three additional cases carrying homozygous c.676dup and three carrying combinations of this and other likely causal variants in M1AP. Moreover, a homozygous missense variant p.(Pro389Leu) segregated with infertility in five men from a consanguineous Turkish family (LOD score = 3.28). 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 was described for mice with disruption of M1ap. Collectively, these findings demonstrate that mutations in M1AP cause autosomal recessive severe spermatogenic failure and male infertility. In view of the evidences from several independent groups and populations, M1AP should be included in the growing list of validated male infertility genes.
- A de novo paradigm for male infertilityPublication . Oud, M.S.; Smits, R.M.; Smith, H.E.; Mastrorosa, F.K.; Holt, G.S.; Houston, B.J.; de Vries, P.F.; Alobaidi, B.K.S.; Batty, L.E.; Ismail, H.; Greenwood, J.; Sheth, H.; Mikulasova, A.; Astuti, G.D.N.; Gilissen, C.; McEleny, K.; Turner, H.; Coxhead, J.; Cockell, S.; Braat, D.D.M.; Fleischer, K.; D’Hauwers, K.W.M.; Schaafsma, E.; 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.; Nagirnaja, L.; Conrad, D.F.; Friedrich, C.; Kliesch, S.; Aston, K.I.; Riera-Escamilla, A.; Krausz, C.; Gonzaga-Jauregui, C.; Santibanez-Koref, M.; Elliott, D. J.; Vissers, L.E.L.M.; Tüttelmann, F.; O’Bryan, M.K.; Ramos, L.; Xavier, M.J.; van der Heijden, G.W.; Veltman, J.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 < 0.1%) protein-altering de novo mutations are classified as possibly causative of the male infertility phenotype. We observed a significant enrichment of loss-of-function de novo mutations in loss-of-function-intolerant genes (p-value = 1.00 × 10−5) in infertile men compared to controls. Additionally, we detected a significant increase in predicted pathogenic de novo missense mutations affecting missense-intolerant genes (p-value = 5.01 × 10−4) in contrast to predicted benign de novo mutations. One gene we identify, RBM5, is an essential regulator of male germ cell pre-mRNA splicing and has been previously implicated in male infertility in mice. In a follow-up study, 6 rare pathogenic missense mutations affecting this gene are observed in a cohort of 2,506 infertile patients, whilst we find no such mutations in a cohort of 5,784 fertile men (p-value = 0.03). Our results provide evidence for the role of de novo mutations in severe male infertility and point to new candidate genes affecting fertility.
- Human spermatogenic failure purges deleterious mutation load from the autosomes and both sex chromosomes, including the gene DMRT1Publication . Lopes, Alexandra; Aston, Kenneth I.; Thompson, Emma E; Carvalho, Filipa; Gonçalves, João; Huang, N.; Matthiesen, Rune; Noordam, Michiel J.; Quintela, Ines; Ramu, Avinash; Seabra, Catarina; Wilfert, Amy B.; Dai, Juncheng; Downie, Jonathan; Fernandes, Susana; Guo, Xuejiang; Shah, Jiahao; Amorim, Antonio; Barros, Alberto; Carracedo, A.; Hu, Z.; Hurles, M.E.; Moskovtsev, S.; Ober, C.; Paduch, D.A.; Schiffman, J.D.; Schlegel, P.N.; Sousa, M.; Carrell, D.T.; Conrad, D.F.Gonadal failure, along with early pregnancy loss and perinatal death, may be an important filter that limits the propagation of harmful mutations in the human population. We hypothesized that men with spermatogenic impairment, a disease with unknown genetic architecture and a common cause of male infertility, are enriched for rare deleterious mutations compared to men with normal spermatogenesis. After assaying genomewide SNPs and CNVs in 323 Caucasian men with idiopathic spermatogenic impairment and more than 1,100 controls, we estimate that each rare autosomal deletion detected in our study multiplicatively changes a man’s risk of disease by 10% (OR 1.10 [1.04–1.16], p,261023), rare X-linked CNVs by 29%, (OR 1.29 [1.11–1.50], p,161023), and rare Y-linked duplications by 88% (OR 1.88 [1.13–3.13], p,0.03). By contrasting the properties of our case-specific CNVs with those of CNV callsets from cases of autism, schizophrenia, bipolar disorder, and intellectual disability, we propose that the CNV burden in spermatogenic impairment is distinct from the burden of large, dominant mutations described for neurodevelopmental disorders. We identified two patients with deletions of DMRT1, a gene on chromosome 9p24.3 orthologous to the putative sex determination locus of the avian ZW chromosome system. In an independent sample of Han Chinese men, we identified 3 more DMRT1 deletions in 979 cases of idiopathic azoospermia and none in 1,734 controls, and found none in an additional 4,519 controls from public databases. The combined results indicate that DMRT1 loss-of-function mutations are a risk factor and potential genetic cause of human spermatogenic failure (frequency of 0.38% in 1306 cases and 0% in 7,754 controls, p = 6.261025). Our study identifies other recurrent CNVs as potential causes of idiopathic azoospermia and generates hypotheses for directing future studies on the genetic basis of male infertility and IVF outcomes.
- Rare double sex and mab-3-related transcription factor 1 regulatory variants in severe spermatogenic failurePublication . Lima, A.C.; Carvalho, F.; Gonçalves, J.; Fernandes, S.; Marques, P.I.; Sousa, M.; Barros, A.; Seixas, A.; Amorim, A.; Conrad, D.F.; Lopes, M.The double sex and mab-3-related transcription factor 1 (DMRT1) gene has long been linked to sex-determining pathways across vertebrates and is known to play an essential role in gonadal development and maintenance of spermatogenesis in mice. In humans, the genomic region harboring the DMRT gene cluster has been implicated in disorders of sex development and recently DMRT1 deletions were shown to be associated with non-obstructive azoospermia (NOA). In this work, we have employed different methods to screen a cohort of Portuguese NOA patients for DMRT1 exonic insertions and deletions [by multiplex ligation probe assay (MLPA); n = 68] and point mutations (by Sanger sequencing; n = 155). We have found three novel patient-specific non-coding variants in heterozygosity that were absent from 357 geographically matched controls. One of these is a complex variant with a putative regulatory role (c.-223_-219CGAAA>T), located in the promoter region within a conserved sequence involved in Dmrt1 repression. Moreover, while DMRT1 domains are highly conserved across vertebrates and show reduced levels of diversity in human populations, two rare synonymous substitutions (rs376518776 and rs34946058) and two rare non-coding variants that potentially affect DMRT1 expression and splicing (rs144122237 and rs200423545) were overrepresented in patients when compared with 376 Portuguese controls (301 fertile and 75 normozoospermic). Overall our previous and present results suggest a role of changes in DMRT1 dosage in NOA potentially also through a process of gene misregulation, even though DMRT1 deleterious variants seem to be rare.