OGRE: calculate, visualize, and analyze overlap between genomic input regions and public annotations.

BACKGROUND: Modern genome sequencing leads to an ever-growing collection of genomic annotations. Combining these elements with a set of input regions (e.g. genes) would yield new insights in genomic associations, such as those involved in gene regulation. The required data are scattered across different databases making a manual approach tiresome, unpractical, and prone to error. Semi-automatic approaches require programming skills in data parsing, processing, overlap calculation, and visualization, which most biomedical researchers lack. Our aim was to develop an automated tool providing all necessary algorithms, benefiting both bioinformaticians and researchers without bioinformatic training. RESULTS: We developed overlapping annotated genomic regions (OGRE) as a comprehensive tool to associate and visualize input regions with genomic annotations. It does so by parsing regions of interest, mining publicly available annotations, and calculating possible overlaps between them. The user can thus identify location, type, and number of associated regulatory elements. Results are presented as easy to understand visualizations and result tables. We applied OGRE to recent studies and could show high reproducibility and potential new insights. To demonstrate OGRE's performance in terms of running time and output, we have conducted a benchmark and compared its features with similar tools. CONCLUSIONS: OGRE's functions and built-in annotations can be applied as a downstream overlap association step, which is compatible with most genomic sequencing outputs, and can thus enrich pre-existing analyses pipelines. Compared to similar tools, OGRE shows competitive performance, offers additional features, and has been successfully applied to two recent studies. Overall, OGRE addresses the lack of tools for automatic analysis, local genomic overlap calculation, and visualization by providing an easy to use, end-to-end solution for both biologists and computational scientists.

Bi-allelic Mutations in M1AP Are a Frequent Cause of Meiotic Arrest and Severely Impaired Spermatogenesis Leading to Male Infertility.

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.

De Novo Mutations in FOXJ1 Result in a Motile Ciliopathy with Hydrocephalus and Randomization of Left/Right Body Asymmetry.

Hydrocephalus is one of the most prevalent form of developmental central nervous system (CNS) malformations. Cerebrospinal fluid (CSF) flow depends on both heartbeat and body movement. Furthermore, it has been shown that CSF flow within and across brain ventricles depends on cilia motility of the ependymal cells lining the brain ventricles, which play a crucial role to maintain patency of the narrow sites of CSF passage during brain formation in mice. Using whole-exome and whole-genome sequencing, we identified an autosomal-dominant cause of a distinct motile ciliopathy related to defective ciliogenesis of the ependymal cilia in six individuals. Heterozygous de novo mutations in FOXJ1, which encodes a well-known member of the forkhead transcription factors important for ciliogenesis of motile cilia, cause a motile ciliopathy that is characterized by hydrocephalus internus, chronic destructive airway disease, and randomization of left/right body asymmetry. Mutant respiratory epithelial cells are unable to generate a fluid flow and exhibit a reduced number of cilia per cell, as documented by high-speed video microscopy (HVMA), transmission electron microscopy (TEM), and immunofluorescence analysis (IF). TEM and IF demonstrate mislocalized basal bodies. In line with this finding, the focal adhesion protein PTK2 displays aberrant localization in the cytoplasm of the mutant respiratory epithelial cells.

Disruption of human meiotic telomere complex genes TERB1, TERB2 and MAJIN in men with non-obstructive azoospermia.

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.

wg-blimp: an end-to-end analysis pipeline for whole genome bisulfite sequencing data.

BACKGROUND: Analysing whole genome bisulfite sequencing datasets is a data-intensive task that requires comprehensive and reproducible workflows to generate valid results. While many algorithms have been developed for tasks such as alignment, comprehensive end-to-end pipelines are still sparse. Furthermore, previous pipelines lack features or show technical deficiencies, thus impeding analyses. RESULTS: We developed wg-blimp (whole genome bisulfite sequencing methylation analysis pipeline) as an end-to-end pipeline to ease whole genome bisulfite sequencing data analysis. It integrates established algorithms for alignment, quality control, methylation calling, detection of differentially methylated regions, and methylome segmentation, requiring only a reference genome and raw sequencing data as input. Comparing wg-blimp to previous end-to-end pipelines reveals similar setups for common sequence processing tasks, but shows differences for post-alignment analyses. We improve on previous pipelines by providing a more comprehensive analysis workflow as well as an interactive user interface. To demonstrate wg-blimp's ability to produce correct results we used it to call differentially methylated regions for two publicly available datasets. We were able to replicate 112 of 114 previously published regions, and found results to be consistent with previous findings. We further applied wg-blimp to a publicly available sample of embryonic stem cells to showcase methylome segmentation. As expected, unmethylated regions were in close proximity of transcription start sites. Segmentation results were consistent with previous analyses, despite different reference genomes and sequencing techniques. CONCLUSIONS: wg-blimp provides a comprehensive analysis pipeline for whole genome bisulfite sequencing data as well as a user interface for simplified result inspection. We demonstrated its applicability by analysing multiple publicly available datasets. Thus, wg-blimp is a relevant alternative to previous analysis pipelines and may facilitate future epigenetic research.

VIPER: a web application for rapid expert review of variant calls.

Summary: With the rapid development in next-generation sequencing, cost and time requirements for genomic sequencing are decreasing, enabling applications in many areas such as cancer research. Many tools have been developed to analyze genomic variation ranging from single nucleotide variants to whole chromosomal aberrations. As sequencing throughput increases, the number of variants called by such tools also grows. Often employed manual inspection of such calls is thus becoming a time-consuming procedure. We developed the Variant InsPector and Expert Rating tool (VIPER) to speed up this process by integrating the Integrative Genomics Viewer into a web application. Analysts can then quickly iterate through variants, apply filters and make decisions based on the generated images and variant metadata. VIPER was successfully employed in analyses with manual inspection of more than 10 000 calls. Availability and implementation: VIPER is implemented in Java and Javascript and is freely available at https://github.com/MarWoes/viper. Contact: marius.woeste@uni-muenster.de. Supplementary information: Supplementary data are available at Bioinformatics online.

Transcriptome analyses in infertile men reveal germ cell-specific expression and splicing patterns.

The process of spermatogenesis-when germ cells differentiate into sperm-is tightly regulated, and misregulation in gene expression is likely to be involved in the physiopathology of male infertility. The testis is one of the most transcriptionally rich tissues; nevertheless, the specific gene expression changes occurring during spermatogenesis are not fully understood. To better understand gene expression during spermatogenesis, we generated germ cell-specific whole transcriptome profiles by systematically comparing testicular transcriptomes from tissues in which spermatogenesis is arrested at successive steps of germ cell differentiation. In these comparisons, we found thousands of differentially expressed genes between successive germ cell types of infertility patients. We demonstrate our analyses' potential to identify novel highly germ cell-specific markers (TSPY4 and LUZP4 for spermatogonia; HMGB4 for round spermatids) and identified putatively misregulated genes in male infertility (RWDD2A, CCDC183, CNNM1, SERF1B). Apart from these, we found thousands of genes showing germ cell-specific isoforms (including SOX15, SPATA4, SYCP3, MKI67). Our approach and dataset can help elucidate genetic and transcriptional causes for male infertility.

Genetic Architecture of Azoospermia-Time to Advance the Standard of Care.

BACKGROUND: Crypto- and azoospermia (very few/no sperm in the semen) are main contributors to male factor infertility. Genetic causes for spermatogenic failure (SPGF) include Klinefelter syndrome and Y-chromosomal azoospermia factor microdeletions, and CFTR mutations for obstructive azoospermia (OA). However, the majority of cases remain unexplained because monogenic causes are not analysed. OBJECTIVE: To elucidate the monogenic contribution to azoospermia by prospective exome sequencing and strict application of recent clinical guidelines. DESIGN, SETTING, AND PARTICIPANTS: Since January 2017, we studied crypto- and azoospermic men without chromosomal aberrations and Y-chromosomal microdeletions attending the Centre of Reproductive Medicine and Andrology, Münster. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We performed exome sequencing in 647 men, analysed 60 genes having at least previous limited clinical validity, and strictly assessed variants according to clinical guidelines. RESULTS AND LIMITATIONS: Overall, 55 patients (8.5%) with diagnostic genetic variants were identified. Of these patients, 20 (3.1%) carried mutations in CFTR or ADGRG2, and were diagnosed with OA. In 35 patients (5.4%) with SPGF, mutations in 20 different genes were identified. According to ClinGen criteria, 19 of the SPGF genes now reach at least moderate clinical validity. As limitations, only one transcript per gene was considered, and the list of genes is increasing rapidly so cannot be exhaustive. CONCLUSIONS: The number of diagnostic genes in crypto-/azoospermia was almost doubled to 21 using exome-based analyses and clinical guidelines. Application of this procedure in routine diagnostics will significantly improve the diagnostic yield and clinical workup as the results indicate the success rate of testicular sperm extraction. PATIENT SUMMARY: When no sperm are found in the semen, a man cannot conceive naturally. The causes are often unknown, but genetics play a major role. We searched for genetic variants in a large group of patients and found causal mutations for one in 12 men; these predict the chances for fatherhood.

A GWAS in Idiopathic/Unexplained Infertile Men Detects a Genomic Region Determining Follicle-Stimulating Hormone Levels.

CONTEXT: Approximately 70% of infertile men are diagnosed with idiopathic (abnormal semen parameters) or unexplained (normozoospermia) infertility, with the common feature of lacking etiologic factors. Follicle-stimulating hormone (FSH) is essential for initiation and maintenance of spermatogenesis. Certain single-nucleotide variations (SNVs; formerly single-nucleotide polymorphisms [SNPs]) (ie, FSHB c.-211G > T, FSHR c.2039A > G) are associated with FSH, testicular volume, and spermatogenesis. It is unknown to what extent other variants are associated with FSH levels and therewith resemble causative factors for infertility. OBJECTIVE: We aimed to identify further genetic determinants modulating FSH levels in a cohort of men presenting with idiopathic or unexplained infertility. METHODS: We retrospectively (2010-2018) selected 1900 men with idiopathic/unexplained infertility. In the discovery study (n = 760), a genome-wide association study (GWAS) was performed (Infinium PsychArrays) in association with FSH values (Illumina GenomeStudio, v2.0). Minor allele frequencies (MAFs) were analyzed for the discovery and an independent normozoospermic cohort. In the validation study (n = 1140), TaqMan SNV polymerase chain reaction was conducted for rs11031005 and rs10835638 in association with andrological parameters. RESULTS: Imputation revealed 9 SNVs in high linkage disequilibrium, with genome-wide significance (P < 4.28e-07) at the FSHB locus 11p.14.1 being associated with FSH. The 9 SNVs accounted for up to a 4.65% variance in FSH level. In the oligozoospermic subgroup, this was increased up to 6.95% and the MAF was enhanced compared to an independent cohort of normozoospermic men. By validation, a significant association for rs11031005/rs10835638 with FSH (P = 4.71e-06/5.55e-07) and FSH/luteinizing hormone ratio (P = 2.08e-12/6.4e-12) was evident. CONCLUSIONS: This GWAS delineates the polymorphic FSHB genomic region as the main determinant of FSH levels in men with unexplained or idiopathic infertility. Given the essential role of FSH, molecular detection of one of the identified SNVs that causes lowered FSH and therewith decreases spermatogenesis could resolve the idiopathic/unexplained origin by this etiologic factor.

Whole-genome methylation analysis of testicular germ cells from cryptozoospermic men points to recurrent and functionally relevant DNA methylation changes.

BACKGROUND: Several studies have reported an association between male infertility and aberrant sperm DNA methylation patterns, in particular in imprinted genes. In a recent investigation based on whole methylome and deep bisulfite sequencing, we have not found any evidence for such an association, but have demonstrated that somatic DNA contamination and genetic variation confound methylation studies in sperm of severely oligozoospermic men. To find out whether testicular germ cells (TGCs) of such patients might carry aberrant DNA methylation, we compared the TGC methylomes of four men with cryptozoospermia (CZ) and four men with obstructive azoospermia, who had normal spermatogenesis and served as controls (CTR). RESULTS: There was no difference in DNA methylation at the whole genome level or at imprinted regions between CZ and CTR samples. However, using stringent filters to identify group-specific methylation differences, we detected 271 differentially methylated regions (DMRs), 238 of which were hypermethylated in CZ (binominal test, p < 2.2 × 10-16). The DMRs were enriched for distal regulatory elements (p = 1.0 × 10-6) and associated with 132 genes, 61 of which are differentially expressed at various stages of spermatogenesis. Almost all of the 67 DMRs associated with the 61 genes (94%) are hypermethylated in CZ (63/67, p = 1.107 × 10-14). As judged by single-cell RNA sequencing, 13 DMR-associated genes, which are mainly expressed during meiosis and spermiogenesis, show a significantly different pattern of expression in CZ patients. In four of these genes, the promoter is hypermethylated in CZ men, which correlates with a lower expression level in these patients. In the other nine genes, eight of which downregulated in CZ, germ cell-specific enhancers may be affected. CONCLUSIONS: We found that impaired spermatogenesis is associated with DNA methylation changes in testicular germ cells at functionally relevant regions of the genome. We hypothesize that the described DNA methylation changes may reflect or contribute to premature abortion of spermatogenesis and therefore not appear in the mature, motile sperm.

Calcitonin receptor-like (CALCRL) is a marker of stemness and an independent predictor of outcome in pediatric AML.

We have recently identified the G protein-coupled neuropeptide receptor calcitonin receptor-like (CALCRL) as an independent prognostic biomarker and a therapeutic target in more than 1500 adult patients with acute myeloid leukemia (AML). Here, we confirmed CALCRL expression as a prognostic factor in a cohort of 284 pediatric patients with AML. High CALCRL expression was independently associated with event-free survival (hazard ratio [HR], 1.87; 95% confidence interval [CI], 1.36-2.57; P = .0001), overall survival (HR, 1.55; 95% CI, 1.06-2.27; P = .025), and cumulative incidence of relapse (HR, 2.10; 95% CI, 1.49-1.96; P < .0001) when adjusting for age, white blood cell count, and genetic risk. Despite its association with leukemia stem cell signatures, CALCRL expression remained associated with all end points when compared with the 17-gene leukemic stem cell score. The strong association of CALCRL expression with the risk of relapse also in the pediatric population supports its role as novel age-independent master regulator of relapse-initiating, drug-tolerant AML cells in humans.

TRIM71 Deficiency Causes Germ Cell Loss During Mouse Embryogenesis and Is Associated With Human Male Infertility.

Mutations affecting the germline can result in infertility or the generation of germ cell tumors (GCT), highlighting the need to identify and characterize the genes controlling germ cell development. The RNA-binding protein and E3 ubiquitin ligase TRIM71 is essential for embryogenesis, and its expression has been reported in GCT and adult mouse testes. To investigate the role of TRIM71 in mammalian germ cell embryonic development, we generated a germline-specific conditional Trim71 knockout mouse (cKO) using the early primordial germ cell (PGC) marker Nanos3 as a Cre-recombinase driver. cKO mice are infertile, with male mice displaying a Sertoli cell-only (SCO) phenotype which in humans is defined as a specific subtype of non-obstructive azoospermia characterized by the absence of germ cells in the seminiferous tubules. Infertility in male Trim71 cKO mice originates during embryogenesis, as the SCO phenotype was already apparent in neonatal mice. The in vitro differentiation of mouse embryonic stem cells (ESCs) into PGC-like cells (PGCLCs) revealed reduced numbers of PGCLCs in Trim71-deficient cells. Furthermore, TCam-2 cells, a human GCT-derived seminoma cell line which was used as an in vitro model for PGCs, showed proliferation defects upon TRIM71 knockdown. Additionally, in vitro growth competition assays, as well as proliferation assays with wild type and CRISPR/Cas9-generated TRIM71 mutant NCCIT cells showed that TRIM71 also promotes proliferation in this malignant GCT-derived non-seminoma cell line. Importantly, the PGC-specific markers BLIMP1 and NANOS3 were consistently downregulated in Trim71 KO PGCLCs, TRIM71 knockdown TCam-2 cells and TRIM71 mutant NCCIT cells. These data collectively support a role for TRIM71 in PGC development. Last, via exome sequencing analysis, we identified several TRIM71 variants in a cohort of infertile men, including a loss-of-function variant in a patient with an SCO phenotype. Altogether, our work reveals for the first time an association of TRIM71 deficiency with human male infertility, and uncovers further developmental roles for TRIM71 in the germline during mouse embryogenesis.

CopyDetective: Detection threshold-aware copy number variant calling in whole-exome sequencing data.

BACKGROUND: Copy number variants (CNVs) are known to play an important role in the development and progression of several diseases. However, detection of CNVs with whole-exome sequencing (WES) experiments is challenging. Usually, additional experiments have to be performed. FINDINGS: We developed a novel algorithm for somatic CNV calling in matched WES data called "CopyDetective". Different from other approaches, CNV calling with CopyDetective consists of a 2-step procedure: first, quality analysis is performed, determining individual detection thresholds for every sample. Second, actual CNV calling on the basis of the previously determined thresholds is performed. Our algorithm evaluates the change in variant allele frequency of polymorphisms and reports the fraction of affected cells for every CNV. Analyzing 4 WES data sets (n = 100) we observed superior performance of CopyDetective compared with ExomeCNV, VarScan2, ControlFREEC, ExomeDepth, and CNV-seq. CONCLUSIONS: Individual detection thresholds reveal that not every WES data set is equally apt for CNV calling. Initial quality analyses, determining individual detection thresholds-as realized by CopyDetective-can and should be performed prior to actual variant calling.

The sperm epigenome does not display recurrent epimutations in patients with severely impaired spermatogenesis.

BACKGROUND: In the past 15 years, numerous studies have described aberrant DNA methylation of imprinted genes (e.g. MEST and H19) in sperm of oligozoospermic men, but the prevalence and genomic extent of abnormal methylation patterns have remained unknown. RESULTS: Using deep bisulfite sequencing (DBS), we screened swim-up sperm samples from 40 normozoospermic and 93 patients diagnosed as oligoasthenoteratozoospermic, oligoteratozoospermic or oligozoospermic, which are termed OATs throughout the manuscript, for H19 and MEST methylation. Based on this screening, we defined three patient groups: normal controls (NC), abnormally methylated oligozoospermic (AMO; n = 7) and normally methylated oligozoospermic (NMO; n = 86). Whole-genome bisulfite sequencing (WGBS) of five NC and five AMO samples revealed abnormal methylation levels of all 50 imprinting control regions in each AMO sample. To investigate whether this finding reflected epigenetic germline mosaicism or the presence of residual somatic DNA, we made a genome-wide inventory of soma-germ cell-specific DNA methylation. We found that > 2000 germ cell-specific genes are promoter-methylated in blood and that AMO samples had abnormal methylation levels at these genes, consistent with the presence of somatic cell DNA. The comparison between the five NC and six NMO samples revealed 19 differentially methylated regions (DMRs), none of which could be validated in an independent cohort of 40 men. Previous studies reported a higher incidence of epimutations at single CpG sites in the CTCF-binding region 6 of H19 in infertile patients. DBS analysis of this locus, however, revealed an association between DNA methylation levels and genotype (rs2071094), but not fertility phenotype. CONCLUSIONS: Our results suggest that somatic DNA contamination and genetic variation confound methylation studies in sperm of infertile men. While we cannot exclude the existence of rare patients with slightly abnormal sperm methylation at non-recurrent CpG sites, the prevalence of aberrant methylation in swim-up purified sperm of infertile men has likely been overestimated, which is reassuring for patients undergoing assisted reproduction.