Search Results - EGA European Genome-Phenome Archive

Characterization of Autosomal CNV Among the Negrito from Peninsular Malaysia

Copy number variation (CNV) has been recognized as a major contributor to human genome diversity. It plays an important role in determining phenotypes and has been associated with a number of common and complex diseases. However the CNV data from diverse populations is rather limited. Here we report the first investigation of copy number variation (CNV) in the indigenous populations from Peninsular Malaysia. We genotyped 34 Negrito genomes from Peninsular Malaysia using the Affymetrix SNP 6.0 microarray and identified 62 putative novel CNVs, consisting of 25 gains and 37 losses. These CNVs appear unique to the Negrito population and were absent in the DGV, HapMap3 and Singapore Genome Variation Project (SGVP) datasets. Analysis of gene ontology revealed that genes within these CNVs were enriched in the immune system (GO:0002376), response to stimulus mechanisms (GO:0050896), as well as the metabolic pathways (GO:0001852). Copy number gains in CNVRs enriched with genes were significantly higher than the losses (P value <0.001). Therefore, in view of the small population size, relative isolation and semi-normadic lifestyles of this community, we speculate that these CNVs may be attributed to recent local adaptation of Negritos from Peninsular Malaysia.

Study phs000664

Pharmacogenomic Interactions in Glioblastoma Cell Line Models

Glioblastoma (GBM) is a lethal disease without effective treatments. To advance toward effective therapeutic approaches that are biomarker-driven, there is a need for new targeted agents and to develop accurate preclinical models that encompass its cellular and molecular diversity. Historical cell line models poorly represent molecular diversity of GBMs, so we developed a living tissue bank encompassing 103 patient-derived GBM cell lines (PDGCLs) as a platform for preclinical pharmacogenomic investigation at scale. Thirty-four PDGCLs were submitted to a comprehensive molecular characterization of copy number alterations and mutations using whole exome sequencing (WES) and gene expression (microarrays), and tested against a panel of 390 small molecules at sixteen different duplicated concentrations. After integrating and systematically correlating molecular alterations with drug sensitivities, we yielded 8,083,140 pharmacogenomic interactions, and discovered novel drug and biomarker combinations which help to prioritize highly effective novel candidate treatments in GBM. Our findings demonstrate the utility of deep characterization of large numbers of models from a single disease to detect complex predictors of compound sensitivity, and indicate novel therapeutic approaches for a large fraction of patients with GBM.

Study phs001793

Reasons for Geographic and Racial Differences in Stroke Cardiorenal GWAS

REGARDS is a national, population-based, longitudinal study of incident stroke and associated risk factors including over 30,000 Black and White adults aged 45 years or older from all 48 contiguous U.S. states and the District of Columbia. The study was designed to investigate reasons underlying the higher rate of stroke mortality among Black participants compared to White participants and among residents of the Southeastern U.S. compared to other U.S. regions. By design, Black adults and residents of the deep south were oversampled. Between 2003 and 2007 (baseline visit) participants completed a computer-assisted telephone interview to collect demographic information and medication adherence, and an in-home visit for blood pressure measurements and collection of blood and urine samples. Following the baseline visit, participants have been contacted by phone at six-month intervals to obtain information on incident stroke or secondary outcomes. Additionally, samples and data were collected on about 50% of the original cohort during a second study visit an average of 10 years after the baseline visit. Genotyping was performed as part of an ancillary study on 10,788 (84% Black) participants using Illumina MEGA arrays.

Study phs002719

Methotrexate Clearance GWAS in Acute Lymphoblastic Leukemia (ALL) Patients

We estimated the plasma clearance of methotrexate from 1279 acute lymphoblastic leukemia (ALL) patients treated on the Children Oncology Group 9904 and 9905 trials (http://clinicaltrials.gov/show/NCT00005585 and http://clinicaltrials.gov/show/NCT00005596). Patients received either a 24-hour infusion of a 1 g/m2 dose or 4-hour infusion of a 2 g/m2 dose). Methotrexate clearance was lower in older children (p=7 x 10-7), females (p=2.7 x 10-4), and patients who received a delayed intensification phase (p=0.0022). In a genome-wide analysis, methotrexate clearance was associated with polymorphisms in the SLCO1B1 gene (p=2.1 x 10-11), which encodes for an organic anion transporter. This replicates findings using different schedules of high-dose methotrexate in ALL patients treated on St. Jude protocols. A combined meta-analysis yields a p-value of 5.7 x 10-19 for the association of methotrexate clearance with SLCO1B1 SNP rs4149056 (Trevino et al, PMID 19901119 and Ramsey et al, PMID 23233662). This data set includes the dependent variable of methotrexate clearance and all of the SNP data available from arrays.

Study phs000637

Efficacy of Bitter Taste Blockers on Flavor Acceptance in a Human Population

The goal of this project is to determine variation in human bitter perception and the effectiveness of bitter blockers in individuals of different genotypes. The project is based on the parent project titled "Efficacy of bitter taste blockers on flavor acceptance in pediatric population", which addresses how bitter taste perception affects medication compliance. As a part of the parent project, mothers and their children were recruited from the general population of metropolitan Philadelphia through print and internet media as well as from a database of past research participants. Adults (mothers) were evaluated in the laboratory for bitter taste perception for a variety of "Generally Recognized As Safe" (GRAS) bitter compounds using the general Labeled Magnitude Scale (gLMS) which allows subjects to rate sensory intensity. Mothers were also evaluated for perception of the liquid formulation of the drug KaletraTM, a recommended 1st line treatment for infants with HIV infection, whose taste is rejected by some children and accepted well by others. DNA samples from mothers were genotyped as a part of this study to identify (1) novel genes associated with human bitter perception and (2) the ability of compounds to block bitterness.

Study phs000839

Resistance Development in Basal Cell Nevus Syndrome through the Basal to Squamous Transition

While basal cell carcinomas (BCCs) arise from ectopic hedgehog pathway activation and can be treated with pathway inhibitors, sporadic BCCs display high resistance rates, while tumors arising in Gorlin syndrome patients with germline Patched (PTCH1) mutations are uniformly suppressed by inhibitor therapy. In rare cases, Gorlin syndrome patients on long-term inhibitor therapy will develop individual resistant tumor clones that rapidly progress, but the basis of this resistance remains unstudied. Here we report a case of a Smoothened inhibitor (SMOi)-resistant tumor arising in a Gorlin patient on suppressive SMOi for nearly a decade. Using a combination of multi-omics and spatial transcriptomics, we define the tumor populations at the cellular and tissue level to conclude that Gorlin tumors can develop resistance to SMOi through the previously described basal to squamous cell carcinoma transition (BST). Intriguingly, through spatial whole exome genomic analysis, we nominate PCYT2, ETNK1, and the phosphatidylethanolamine biosynthetic pathway as novel genetic suppressors of BST resistance. These observations provide a general framework for studying tumor evolution and provide important clinical insight into mechanisms of resistance to SMOi for not only Gorlin syndrome but sporadic BCCs as well.

Study phs003415

Single Duplex DNA Sequencing with CODEC Detects Mutations with High Sensitivity

Detecting mutations from single DNA molecules is crucial in many fields but challenging. Next generation sequencing (NGS) affords tremendous throughput but cannot directly sequence double-stranded DNA molecules (single duplexes) to discern the true mutations on both strands. Here, we present Concatenating Original Duplex for Error Correction (CODEC) which confers single duplex resolution to NGS. CODEC affords 1,000-fold higher accuracy than NGS, using up to 100-fold fewer reads than Duplex Sequencing. CODEC revealed mutation frequencies of 2.72 x 10-8 in sperm of a 39-year-old individual, and somatic mutations acquired with age in blood cells. CODEC detected genome-wide clonal hematopoiesis mutations from single DNA molecules, single mutated duplexes from tumor genomes and liquid biopsies, microsatellite instability (MSI) with 10-fold greater sensitivity, and mutational signatures and specific tumor mutations with up to 100-fold fewer reads. CODEC enables more precise genetic testing and reveals biologically significant mutations which are commonly obscured by NGS errors. We applied CODEC to clinical colon and breast neoplasm samples and uncovered expected mutational signatures including homologous recombination deficiency (HRD) and MSI.

Study phs003255

Whole-Exome Sequencing Study of Diabetic Nephropathy

To identify rare variants of diabetic kidney disease (DKD), we conducted a whole-exome sequencing (WES) study. This study employed an extreme case–control design, which included a selection of the 593 most rapidly progressing DKD cases from the Chronic Renal Insufficiency Cohort (CRIC) Study (phs000524). In this two-stage WES study of DKD, participants with DKD from the CRIC were compared with control groups of participants without DKD from another cohort in the first stage. Suggestive signals identified in the first stage were confirmed in the second stage analysis among a diverse population with existing whole-genome sequencing (WGS) data. Generalized linear mixed models, which accounted for genetic relatedness and adjusted for age, sex and ancestry, were used to test associations between single variants and DKD. Gene-based aggregate rare variant analyses were conducted using an optimized sequence kernel association test implemented within our mixed model framework. As a result, we identified four novel gene loci, DIS3L2, KRT6B, ERAP2 and NPEPPS, that achieved exome-wide significance and may play an important role in the DKD disease course. This large WES study provides novel insights into DKD's molecular mechanisms.

Study phs003429

Kids First: Pediatric Research Project on the Genomic Analysis of Congenital Diaphragmatic Hernia

The Gabriella Miller Kids First Pediatric Research Program (Kids First) is a trans-NIH effort initiated in response to the 2014 Gabriella Miller Kids First Research Act and supported by the NIH Common Fund. This program focuses on gene discovery in pediatric cancers and structural birth defects and the development of the Gabriella Miller Kids First Pediatric Data Resource (Kids First Data Resource). Both, childhood cancers and structural birth defects are critical and costly conditions associated with substantial morbidity and mortality. Elucidating the underlying genetic etiology of these diseases has the potential to profoundly improve preventative measures, diagnostics, and therapeutic interventions. WGS and phenotypic data from this study are accessible through dbGaP and kidsfirstdrc.org, where other Kids First datasets can also be accessed. In collaboration with the University of Utah, DNA from four families were selected for high-depth WGS (60X) including diaphragm and skin tissue to identify mosaicism. In collaboration with the Broad Institute, DNA from four families underwent linked long read sequencing using 10X Genomics technology. Probands with congenital diaphragmatic hernia/defects and both biological parents enrolled as part of the DHREAMS study.

Study phs001110

Induction of fetal meiotic oocytes from embryonic stem cells in cynomolgus monkeys

Human in vitro oogenesis provides a framework for clarifying the mechanism of human oogenesis. To create its benchmark, it is vital to promote in vitro oogenesis using a model physiologically close to humans. Here, we establish a foundation for in vitro oogenesis in cynomolgus (cy) monkeys: cy female embryonic stem cells harboring one active and one inactive X chromosome (Xa and Xi, respectively) differentiate robustly into primordial germ cell-like cells, which in xenogeneic reconstituted ovaries develop efficiently into oogonia and, remarkably, further into meiotic oocytes at the zygotene stage. This differentiation entails a comprehensive epigenetic reprogramming, including Xi reprogramming, yet, as partly observed in vivo, Xa and Xi remain epigenetically asymmetric with incomplete Xi reactivation. In humans and monkeys, the Xi epigenome in pluripotent stem cells functions as an Xi-reprogramming determinant. We further show that developmental-pathway over-activations with suboptimal up-regulation of relevant meiotic genes impede in vitro meiotic progression. Cy in vitro oogenesis exhibits critical homology with the human system, including with respect to bottlenecks, providing a salient model for advancing human in vitro oogenesis.

Study JGAS000573

Context-specific regulatory genetic variation in MTOR dampens neutrophil-T cell crosstalk in pneumonia-associated sepsis, modulating disease

Sepsis is a heterogeneous clinical syndrome with a high mortality, requiring personalised stratification strategies. Here, we characterise genetic variation that modulates MTOR, a critical regulator of metabolism and immune responses in sepsis. The effects are highly context specific, involving a regulatory element that affects MTOR expression in activated T cells with opposite direction of effect in neutrophils. We show that the G-allele of the lead variant, rs4845987, associated with decreased risk of T2D, reduces MTOR expression in T cells and improves survival in sepsis due to pneumonia, with effects specific to sepsis endotype. Using ex vivo models, we demonstrate that activated T cells promote immunosuppressive sepsis neutrophils through released cytokines, a process dampened by hypoxia and the mTOR inhibitor rapamycin. Our work demonstrates a novel epigenetic mechanism that fine-tunes MTOR transcription and T cell activity via the variant-containing regulatory element, which further exhibits an allelic effect upon vitamin C treatment. These findings reveal how genetic variation interacts with disease state to modulate immune cell-cell communication, providing a patient stratification strategy to inform more effective sepsis treatment.

Study EGAS50000000894

Federated discovery and sharing of genomic data using Beacons

The Beacon Project is a Global Alliance for Genomics & Health (GA4GH) initiative that enables genomic and clinical data sharing across federated networks. The project is working toward developing regulatory, ethics and security guidance to ensure proportionate safeguards for distribution of data according to the GA4GH-developed “Framework for Responsible Sharing of Genomic and Health-Related Data”. Within this Nature Biotechnology Correspondence a description of the Beacon protocol and how it can be used as a model for the federated discovery and sharing of genomic data is offered to the community. A Beacon is defined as a web-accessible service that can be queried for information about a specific allele. A user of a Beacon can pose queries of the form “Have you observed this nucleotide (e.g., C) at this genomic location (e.g., position 32,936,732 on chromosome 13)?” to which the Beacon responds with either “yes” or “no.” In this way, a Beacon allows allelic information of interest to be discovered by a remote searcher with no reference to a specific sample or patient, thereby mitigating privacy risks. The Beacon API (represented as a RESTful web application) provides a technical specification that a Beacon server must implement. The specification is open source and available online here. To simplify the process of lighting a Beacon, a free, open-source reference implementation of the latest specification has been developed. GA4GH is promoting different levels of data access (open, registered, and controlled) for convenience and for compatibility across its projects. Each so-called access tier has distinct visibility and requirements for authorization. For example, ‘open access’ Beacons are accessible to anonymous users of the internet, whereas ‘registered access’ Beacons are accessible to registered users (for example, bona fide researchers and clinicians) who have agreed to a set of conditions of data use. Many of the largest genomic archives, such as dbGaP, the European Genome-phenome Archive and the European Variation Archive, have provided access to variation data through Beacons for some or all of their datasets. Beacons can be interconnected through the Beacon Network, a directory and search engine for Beacons. Although individual Beacons answer the question “Have you observed this allele?”, the Beacon Network answers the question “Who has observed this allele?”. Beacons can be freely registered to the Beacon Network and can be searched independently or in aggregate with other connected Beacons.

Blog federated-discovery-using-beacons

MECOM represses myeloid differentiation through CEBPA downregulation in AML

Transcription factor MECOM, located at 3q26, is essential for hematopoietic stem cells (HSCs) in healthy individuals. Enhancer translocations, due to 3q26 rearrangements, drive out-of-context MECOM expression in an aggressive subtype of leukemia (AML). Aberrantly expressed MECOM is essential for the survival and immature phenotype of these leukemia cells. Direct depletion of MECOM using an endogenous auxin-inducible degron rapidly upregulates expression of myeloid differentiation factor CEBPA. MECOM depletion is also accompanied by a severe loss of CD34 expression and gain of mature myeloid cell surface marker CD15. MECOM exerts its inhibitory effect on differentiation by binding to the +42kb CEBPA enhancer, which is essential for neutrophil development. This is partially dependent on the interaction between MECOM and its essential co-repressor CTBP2, a potential target in this type of AML. We demonstrate that CEBPA overexpression can bypass the MECOM-mediated block of differentiation. In addition, AML patients with MECOM overexpression through enhancer hijacking show significantly reduced CEBPA. Our study provides insight into the mechanism by which MECOM maintains the stem cell state in AML. Furthermore, CEBPA levels are an important read-out for successful targeting of MECOM in 3q26-rearranged AML.

Study EGAS00001008005

Spatial_transcriptome_analysis_of_Paediatric_Thymus

Cell atlas of Paediatric Thymus Cell atlas of Paediatric Thymus - The Human Cell Atlas initiative is an ambitious global research effort which aims to describe every cell in the human body across all developmental stages to generate a reference map to accelerate progress in science and medicine particularly relating to human development and disease. The initiative is led by investigators based at the Wellcome Sanger Institute and the Broad Institute of MIT and Harvard and funding support from the Wellcome and NIH. We aim to interrogate the cellular composition and molecular regulators underpinning a cells identity through; genetic and genomic analysis, expression analysis, non-identifiable video imaging and cell line and organoid production, as well as, computational algorithms to predict cellular developmental trajectories and cell-cell interactions. We will subsequently validate these findings in situ using spatial genomic and imaging technologies e.g. immunohistochemistry, RNAscope, in situ sequencing and spatial transcriptomic analyses. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/

Study EGAS00001004281

Identification of rare germline variants in familial multiple myeloma

The risk of developing multiple myeloma (MM) in first-degree relatives of affected individuals is 2 to 4 fold higher than in the general population, implying the existence of inherited susceptibility. While over 20 common, low-penetrance variants have been associated with MM risk, less is known about rare, high-penetrance germline predisposition. We aimed to identify and characterize high/moderated penetrance germline variants in MM families using whole genome sequencing. For that purpose we identified families with at least two individuals diagnosed with MM or its precursors MGUS and smoldering MM. Also, patients with solitary plasmacytoma and AL amyloidosis were enrolled. We also recruited unaffected family members, and they were screened to exclude undetected MM or its precursor stages. After whole genome sequencing of blood DNA and filtering for rare variants (minor allele frequency <0.1%) and family segregation, variants are prioritized by a range of published in silico tools and literature search. The most promising variants are subjected to experimental validation to evaluate their functional relevance. Our data will provide guidance to worldwide efforts to unravel germline predisposition in MM and validation of the proposed variants and genes.

Study EGAS00001004734

Resequencing (MIPS) of candidate genes for Keratoconus (2020)

In this study, we selected 34 candidate genes for KC based on previous Whole Exome Sequencing (WES) and the literature, and resequenced them in 745 KC patients and 810 ethnically matched controls. Data analysis was performed using the single variant association test as well as gene-based mutation burden and variance components tests. In our study, we detected enrichment of genetic variation across multiple gene-based tests for the genes COL2A1, COL5A1, TNXB, ZEB1 and ZNF469. The top hit in the Fisher’s exact test was obtained for a common variant in the COL12A1 gene. Interestingly, COL5A1, TNXB, ZNF469 and COL12A1 are all known Ehlers-Danlos Syndrome (EDS) genes. Though the co-occurrence of KC and EDS has been reported previously, this study is the first to demonstrate a consistent role of genetic variants in EDS genes in the etiology of KC. In conclusion, our data show a shared genetic etiology between KC and EDS, and clearly confirm the currently disputed role of ZNF469 in disease susceptibility for KC. Besides the role for EDS genes, we also confirm the previously reported involvement of genetic variation in ZEB1 in KC.

Study EGAS00001004267

MGP Panel: a comprehensive targeted genomics panel for molecular profiling of multiple myeloma patients

We designed a comprehensive multiple myeloma (MM) targeted sequencing panel to identify common genomic abnormalities in a single assay and validated it against known standards. The panel comprised 228 genes/exons for mutations, 6 regions for translocations, and 56 regions for copy number abnormalities (CNAs). Toward panel validation, targeted sequencing was conducted on 233 patient samples and further validated using clinical fluorescence in situ hybridization (FISH) (translocations), multiplex ligation probe analysis (MLPA) (CNAs), whole genome sequencing (WGS) (CNAs, mutations, translocations) or droplet digital PCR (ddPCR) of known standards (mutations). Canonical IgH translocations were detected in 43.2% of patients by sequencing, and aligned with FISH except for one patient. CNAs determined by sequencing and MLPA for 22 regions were comparable in 103 samples and concordance between platforms was R2=0.969. VAFs for 74 mutations were compared between sequencing and ddPCR with concordance of R2=0.9849. In summary, we have developed a targeted sequencing panel that is as robust or superior to FISH and WGS. This molecular panel is cost effective, comprehensive, clinically actionable and can be routinely deployed to assist risk stratification at diagnosis or post-treatment to guide sequencing of therapies.

Study EGAS00001006222

HLA-DR is absent in primitive macrophages through epigenetic silencing of master regulator CIITA

The earliest macrophages are generated during embryonic development from erythro-myeloid progenitors (EMPs) via primitive haematopoiesis. This process is poorly understood in humans and in the mouse is thought to be spatially restricted to the yolk sac. Human fetal placental macrophages, Hofbauer cells (HBC), arise during the primitive haematopoietic wave at ~18 days post conception. Here we identify a population of placental erythro-myeloid progenitors (PEMPs) in the early human placenta that give rise to HBC. PEMP are fetal CD34+CD43+ progenitors found exclusively at early gestational timepoints. Transcriptomic analyses reveal that PEMP have conserved features of primitive yolk sac EMPs, including the lack of HLF expression. Using in vitro single-cell culture experiments we show that PEMP generate HBC-like cells that completely lack HLA-DR expression and demonstrate that this is a conserved feature of all macrophages generated by primitive haematopoiesis in humans. Finally, we demonstrate that the class II transactivator, CTIIA, the master regulator HLA-DR expression, is epigenetically silenced during primitive haematopoiesis, leading to HLA-DRneg macrophages. These findings demonstrate that HBC are derived locally from PEMP and establish the human placenta as an additional site of primitive haematopoiesis.

Study EGAS00001006981

Identification of intronic sequences promoting natural skipping of ABCA4 exon 15 using long-read transcriptomics and midigene assays

Stargardt disease is an inherited retinal disease that leads to progressive loss of vision, and is caused by biallelic variants in the ABCA4 gene. A significant proportion of ABCA4 variants of variable penetrance affect pre-mRNA splicing. Previously, we observed the exclusion of certain ABCA4 exons into the final transcript in the absence of any disease-causing variants. In this study, we explored this phenomenon that we coined natural exon skipping (NES) for the entire ABCA4 transcript, using targeted RT-PCR analysis as well as long-read transcriptome sequencing of control retina samples. For the most abundant NES event, which is skipping of ABCA4 exon 15, overlapping ABCA4 deletion constructs were employed to identify responsible cis-regulatory sequence motifs. Subsequently, antisense oligonucleotides (AONs) were designed and tested to reverse NES and restore fully-spliced ABCA4 mRNA. We identified intronic regions on each side of exon 15 that, when deleted, increased the inclusion of exon 15 in the final transcripts. Interestingly, these motifs appear to work in a synergistic manner. Further fine-mapping of these regions revealed several cis-regulatory motifs that may be responsible for inducing NES, on each side of the exon. AONs targeting these motifs unfortunately did not decrease the skipping of exon 15. In conclusion, we discovered an intriguing phenomenon that, in the absence of disease-causing variants, results in the skipping of one or more exons in the ABCA4 transcript. These NES events appear to be regulated by cis-regulatory motifs within the flanking introns. This work captured the extend of NES throughout ABCA4 transcript and the role of cis-regulatory motifs in pre-mRNA splicing.. The use of AONs targeting cis-regulatory motifs is an innovative strategy for splicing modulation, suitable for complementing future variant-specific splicing modulation therapies in ABCA4 retinopathies.

Study EGAS50000000071

14970 results for "cancer studies using rna-seq"

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