Search Results - EGA European Genome-Phenome Archive

Genomic Characterization of Duke Melanoma Brain Metastases

Previous work has shown that melanoma brain metastases (MBM) have a unique molecular profile compared to extracranial metastases (ECM). Description of the biology of MBM and associations between biological features and clinical outcomes will facilitate the design of rational therapies for patients with MBM. To better characterize the molecular profile of MBM, we conducted whole exome sequencing (WES) and total RNA sequencing on MBM tissues obtained from an independent cohort of 14 patients from Duke University Medical Center. This cohort adds valuable patient samples to the field and enables strengthened investigation of somatic mutations and gene expression profiles within and between cohorts. The mutational landscape and gene expression of MBM from the Duke cohort resembled those previously reported in a previously published dataset of WES and RNA sequencing in MBM and matched ECM tissues from UT MD Anderson Cancer Center (Fischer et al., 2019 30787016). Duke MBM demonstrated similar rates of mutations in genes associated with melanoma, including BRAF, NRAS, and PTEN, as the MD Anderson cohort. Immune populations in MBM were similar between Duke and MD Anderson MBM, though Duke samples demonstrated more resting CD4+ memory T cells. The ratio of M2 to M1 macrophages in the Duke cohort was similar to that of the MD Anderson cohort. In MBM, a higher M2:M1 ratio may contribute to an immune-suppressive tumor microenvironment. Sequencing data and sample attributes from MBM tissues obtained from 14 patients from Duke University Medical Center will be available through dbGaP.

Study phs003009

Whole-genome and transcriptome versus panel sequencing in precision oncology: A translational-clinical comparison

Precision oncology offers new cancer treatment options. While the use of whole-genome (WGS) and transcriptome (TS) sequencing remains often confined to specific clinical programs, molecular analysis with gene panels is more common clinical practice. Methods: Twenty patients with rare or advanced tumors sequenced by WGS/TS within the DKFZ/NCT/DKTK-MASTER program from 2015 to 2020 (MASTER 1) were additionally sequenced with the TSO500 DNA and TST170 RNA Assay by Illumina. Original Molecular Tumor Board (MTB) therapy recommendations (TR) were juxtaposed with TR from NGS panel data analysis (comparison 1). To mitigate temporal differences between the two sequencings, WGS/TS was bioinformatically reanalyzed (MASTER 2), and new TR were again compared (comparison 2). Results: In comparison 1, 47.1% of the MASTER 1’s TR and 62.8% of the panel’s TR were identical, as were 45.9% of the TR of MASTER 2 and 54.9% of the panel in comparison 2. In both MASTER 1 and MASTER 2, 26.5% and 36.1% of TR, respectively, relied on Biomarkers (BM) which were not covered by the panel. Eight of the ten MTB-derived therapy implementations were also supported in the panel, the two remaining ones being based on BM absent from the panel. Conclusions: About half of the TR in WGS/TS and panel sequencing were identical. Around a third of TR issued by WGS/TS were based on BM which are not covered by the panel, leading to therapy implementations. The presented data underscores the clinical value of comprehensive molecular analyses in individuals with advanced cancers.

Study EGAS50000000431

Singel-cell RNA sequencing and CUT&RUN sequencing of human RUNX2-deficient osteoblasts

Runx2 is a master regulator of bone formation, and its dysfunction causes cleidocranial dysplasia (CCD) in humans. When iPS cells were generated from patients with CCD and Runx2-deficient iPS cells were generated using gene-editing techniques, abnormal laminopathy-like nuclei were observed. Runx2-deficient cells showed reduced Lamin A/C expression, but not protein levels. However, in Runx2-deficient cells, both the gene expression and protein levels of Nesprin-1 were reduced, perinuclear actin fibers were sparser, and nuclear stiffness was reduced. Forced expression of Lamin A/C increased nuclear stiffness but did not improve nuclear morphology. In contrast, the induction of Nesprin-1 expression alone normalized nuclear stiffness and restored nuclear morphology and perinuclear actin distribution. In Runx2-null cells, mechanical stress-induced phosphorylation of emerin was not observed. In contrast, forced expression of nesprin-1 in Runx2-null cells resulted in phosphorylation of emerin, indicating the restoration of intracellular tension. These observations were confirmed by atomic force microscopy. Therefore, the intracellular tension was inferred to pull the nuclear membrane into its normal shape. CUT&RUN assay and single RNA-seq analysis showed that an aberrant nuclear membrane caused loss of nuclear lamina gene regulation machinery, making the progression of normal osteogenic differentiation impossible; however, supplementation with Nesprin-1 restored gene regulation mechanisms and promoted pre-osteoblast formation with normal nuclear morphology. Nesprin-1 expression induced by Runx2 is essential for epigenetic regulation of the nuclear lamina. We propose CCD as a new type of laminopathy involving defective expression of Nesprin-1 regulated by Runx2.

Study JGAS000663

Mutational signatures in normal tissues of patients treated with clinical stage G-quadruplex binder CX5461

Drug induced photoreactions following exposure to UVA have been documented for several therapeutic compound classes, including psoralens and fluoroquinolones. CX5461, a quinolone-derived small molecule currently in phase 1 studies for cancer treatment, has been shown to be a clinically significant UV photosensitizer. Here we examined the mutagenic spectrum of CX5461 in normal tissues of patients undergoing treatment, by comparing deep whole genome sequencing (WGS) from skin biopsies taken from non-sun exposed areas pre and post drug exposure of patients in the Canadian Cancer Clinical Trials Group (CCTG) IND.231 trial (NCT02719977). We show that a low burden of SNVs (<100) and indels (<40) mutations was detected in post CX5461 skin biopsies, with a pattern resembling background or sequencing artefact signatures. To further characterize the mutational pattern of CX5461 photoreactivity, we compared mutational profiles of human retinal pigment epithelial cells exposed to UVA, CX5461, or a combination of both UV and CX5461. Treatment with CX5461 or UVA alone, resulted in a low SNV burden. In contrast, human cells exposed to UVA and CX5461 had a two to four orders higher mutational burden, with a distinct mutational pattern characterized by T>A, T>C mutations, dissimilar to that of UV alone or CX5461 alone. Our results suggest that human exposure to CX5461 alone is not associated with high levels of single base mutagenesis. However, CX5461 is a very potent UV photosensitizer, underscoring the need for adequate UV screening and controls when studying the effects of photosensitizing small molecules on single base DNA variation.

Study EGAS50000001145

Transcriptome profiling of megakaryocytes and platelets: application to GP9- and IKZF5-related thrombocytopenia

Platelets are anucleate cells produced in the bone marrow and derived from large progenitor cells called megakaryocytes (MKs). Platelets receive RNA transcripts from their progenitorial MKs during thrombopoiesis. However, the correspondence between platelet and MK transcriptomes is poorly understood, particularly in the context of germline mutations that cause platelet formation defects or thrombocytopenia. We have studied the effects of two such mutations on MK and platelet transcriptomes. We generated immortalized MK cell line (imMKCL)-based models of Bernard-Soulier syndrome and IKZF5-related thrombocytopenia. MKs derived from imMKCLs with either a homozygous deletion of GP9 (GP9-/-) or a heterozygous Y121F variant in IKZF5 (IKZF5WT/Y121F) exhibited reduced proplatelet formation (reductions of 96% and 57%, respectively). Platelets from patients with either GP9-/- or IKZF5WT/Y121F genotypes had broad transcriptomic dysregulation, suggesting that (pro)platelet formation defects due to mutations in glycoprotein receptor and transcription factor genes such as GP9 and IKZF5 affect the trafficking of transcripts from MKs into platelets. RNA-seq data from MKs at four stages of differentiation revealed widespread but distinct changes in expression over time between the GP9-/- and the IKZF5WT/Y121F genotypes. Dysregulated genes in GP9-/- MKs were enriched for RNA metabolism and actin/tubulin folding pathways while those in IKZF5WT/Y121F MKs were enriched for cell cycle pathways. Most of these genes were also dysregulated in the platelets of patients with the corresponding diseases. Our results suggest that patients with inherited forms of thrombocytopenia present with a transcript trafficking defect during platelet formation.

Study EGAS50000001276

Complex genotype-phenotype relationships shape the response to treatment of Down Syndrome Childhood Acute Lymphoblastic Leukaemia

Extensive genetic and epigenetic variegation has been demonstrated in many malignancies. Importantly, their interplay has the potential to contribute to disease progression and treatment resistance. To shed light on the complex relationships between these different sources of intra-tumour heterogeneity, we explored their relative contributions to the evolutionary dynamics of Acute Lymphoblastic Leukaemia (ALL) in children with Down syndrome, which has particularly poor prognosis. We quantified the tumour propagating potential of genetically distinct sub-clones using serial transplantation assays and SNP-arrays. While most leukaemias were characterized by a single dominant subclone, others were highly heterogeneous. Importantly, we provide clear and direct evidence that genotypes and phenotypes with functional relevance to leukemic progression and treatment resistance can co-segregate within the disease. Hence, individual genetic lesions can be restricted to well-defined cell immunophenotypes, corresponding to different stages of the leukemic differentiation hierarchy and varied proliferation potentials. As a result of this difference in fitness, which can be accurately quantified via competitive transplantation assays, matching diagnostic, post-treatment, and relapse leukaemias can be dominated by different genotypes, including pre-leukemic clones persisting throughout the disease progression and treatment. Intriguingly, plasticity also appears to be a temporally defined property that can segregate with genotype. These results suggest that Down Syndrome ALL should be viewed as a complex matrix of cells exhibiting genetic and epigenetic heterogeneity that foster extensive clonal evolution and competition. Therapeutic intervention reshapes this ‘eco-system’ and may provide the right conditions for the preferential expansion of selected compartments and subsequently relapse.

Study EGAS50000001287

Comprehensive genomic analysis of colorectal cancer with microsatellite instability

Microsatellite instability-high (MSI-H) colorectal cancers (CRCs) account for 10?15% of all CRCs. MSI-H CRC is characterized by a large number of somatic insertions/deletions (indels) resulting from either mutations within or the silencing of genes involved in the DNA mismatch repair (MMR) system. A subset of MSI-H CRCs is associated with Lynch syndrome (LS), which is caused by germline MMR gene mutations, leading to hereditary cancer predisposition. Other than frequent somatic mutations in BRAF, the transformation mechanisms underlying MSI-H CRC are largely unknown. Here, genomic DNA from 149 MSI-H CRC specimens was analyzed using whole-exome sequencing, and 93 of these samples were subjected to genome-wide DNA methylation analysis. Furthermore, transcriptome sequencing was conducted on 111 samples. Genomic/epigenomic analyses identified three subgroups within our cohort: (1) MSI-H CRCs with silenced MLH1 that share frequent indels, a specific mutation/copy number alteration profile and promoter DNA methylation; (2) LS-associated MSI-H CRCs with MMR genes containing germline mutations; and (3) the remaining MSI-H CRCs with frequent somatic disruptive mutations of MLH1 or MSH2. Unexpectedly, only the first group was found to frequently carry fusion-type protein kinases (15% of this group and 9.9% of all MSI-H CRCs) that are promising therapeutic targets. Thus, MSI-H CRCs can be classified into three subgroups with distinctive genomic as well as epigenomic statuses, probably reflecting the oncogenic processes of these cancers. Fusion-type kinases are enriched in MSI-H CRCs, shedding new light on potential treatment strategies.

Study JGAS000113

Durable clinical impacts and mechanisms of action and resistance in histone K27 methylation-targeting epigenetic therapy

Epigenomes allow the rectification of disordered cancer gene expressions, thereby providing new targets for pharmacological interventions in cancer therapy. The clinical utility of targeting histone H3 lysine tri-methylation (H3K27me3) as an epigenetic hallmark has been demonstrated. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumor cells remain unclear. Here we show the potency and mechanisms of action and resistance of a newly developed EZH1/2 dual inhibitor, valemetostat, in the clinical trials of patients with adult T-cell leukemia/lymphoma (ATL). Valemetostat administration reduced the tumor size and demonstrated durable clinical benefits. Integrative single-cell analyses of patients before and after the administration of valemetostat showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, such as tumor suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. The acquired mutations at the EZH2???compound interface result in the propagation of the clones with re-increased H3K27me3. In patients free of this mutation, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation at the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting chromatin homeostasis might provide opportunities for further sustained epigenetic cancer therapies.

Study JGAS000553

CAGE-seq analysis of osteoblast derived from cleidocranial dysplasia human induced pluripotent stem cells

Non-coding RNAs (ncRNAs) comprise a major portion of transcripts and serve an essential role in biological processes. Although the importance of major transcriptomes in osteogenesis has been extensively studied, the function of ncRNAs in human osteogenesis remains unclear. Previously, we developed hiPSCs from patients with cleidocranial dysplasia (CCD) caused by runt-related transcription factor 2 (RUNX2) haploinsufficiency. To gain insight into ncRNAs in osteogenesis, we surveyed differential ncRNA expression profiling and promoter differences of RUNX2 using patient-specific iPSCs and cap analysis gene expression (CAGE) technology to define the promoter landscape. Revertant iPSCs (Rev1 iPSCs) edited by CRISPR/Cas9 system to harbor mutation-corrected RUNX2 exhibited increased proximal promoter expression of RUNX2, while CCD iPSCs did not. We identified 2271 ncRNA genes with altered expression levels before and after differentiation, 31 of which showed at least 20-fold higher expression in Rev1 iPSCs. Bioinformatic analysis also categorized AC007392.3, LINC00379, RP11-122D10.1, and RP11-90J7.2 as enhancer regulatory regions, and HOXA-AS2, MIR219-2, and RP11-834C11.3 as dyadic regulatory regions of these ncRNAs. In addition, two miRNAs, termed MIR199A2 and MIR152, were found to have high enrichment of osteogenic-related terms. Upon further examination of the role of MIR152 on osteoblast differentiation, we found that MIR152 knockdown induced upregulation of ALP and COL1A1 in Saos-2 cells. Thus, ncRNAs were found to regulate the osteogenic differentiation potentials of hiPSCs that are used for bone regeneration and repair owing to their differentiation potentials. These data allow understanding ncRNA profiles of hiPSCs during osteogenesis.

Study JGAS000248

Sequence analysis of colorectal serrated lesions

Recent studies have shown that colorectal serrated lesions, which include sessile serrated adenomas (SSAs) and traditional serrated adenomas (TSAs), are precursors of colorectal cancer. However, the molecular mechanisms underlying the carcinogenesis, particularly in TSAs, remain largely uncharacterized. To clarify their molecular and clinicopathological characteristics, we performed mutation and methylation analyses of cancer-associated genes in 78 serrated lesions, including TSAs, SSAs and microvesicular hyperplastic polyps. Target exon sequence analysis was performed with 39 genes, including genes known to be frequently mutated in colorectal cancers and/or serrated lesions. We also used bisulfite pyrosequencing to assess the methylation status of various cancer-associated genes and marker genes of the CpG island methylator phenotype (CIMP). The prevalence of mutations in genes associated with Wnt signaling was significantly higher in TSAs than SSAs (65% vs. 28%, p < 0.01). Among those, RNF43 mutations were observed in 38% of TSAs and 17% of SSAs. In immunohistochemical studies of 39 serrated lesions, the prevalence of abnormal nuclear ?-catenin accumulation was significantly higher in TSAs (57%) than SSAs (8%) (P = 0.01). SMOC1 methylation was detected in 54% of TSAs but in no SSAs (p < 0.01). Additionally, SMOC1 methylation was more prevalent among TSAs with KRAS mutation (82%) than with BRAF mutation (38%, p = 0.03). Lesions with CIMP-high or RNF43 mutations were detected only in TSAs with BRAF mutation, suggesting two distinct carcinogenic pathways in TSAs. Mutations in genes associated with Wnt signaling play a greater role in the carcinogenesis of TSAs than SSAs.

Study JGAS000217

Innate myeloid cell sbuset-specific gene expression patterns in the human colon are altered in Crohn's disease patients

Background: There is a heterogeneous subset innate myeloid cells, such as macrophages and dendritic cells, in the human intestinal lamina propria. Several studies have demonstrated that these cells contribute to the maintenance of gut homeostasis through induction of inflammatory responses and tolerance via cell type-specific mechanisms; whereas, disrupted innate immune responses are implicated in the pathogenesis of Crohn?s disease. However, the detailed mechanisms by which each innate myeloid subset regulates gut homeostasis and inflammation largely remains unknown. Aim: We aimed to clarify the comprehensive gene expression profiles of innate myeloid cell subsets in the lamina propria from normal human colons (NC) and the inflamed colon sites from patients with Crohn?s disease (CDi). Methods: We performed RNA-sequencing analysis and precise bioinformatics analysis on three innate myeloid cell subsets, CD14-CD11c-, CD14-CD11c+, and CD14+CD11c+CD163low cells from NC and CDi. Results: Transcriptional analysis of the three subsets from the NC showed distinct gene expression patterns and gene ontology (GO) enrichment analysis revealed the associated innate myeloid subset-specific biological process (BP) terms. In addition, changes in gene expression patterns were observed in innate myeloid subsets from CDi. Furthermore, the core GO-BP terms for the genes upregulated in the innate myeloid cells from CDi were distinct from those found in NC. Conclusion: Our data identified the innate myeloid cell subset-specific transcriptomes and the associated enriched GO-BP terms in the NC and found these patterns were altered in CDi.

Study JGAS000127

DNA demethylation is associated with malignant progression of low-grade gliomas

To elucidate the mechanisms of tumor progression is key to discovering strategies for treating patients with lower-grade glioma. Thus to characterize the changes in the molecular profile during malignant progression, we performed methylation array analysis (122 tumors), whole-exome sequencing (36 tumors and matched normal samples), and RNA sequencing (31 tumors). This cohort included 24 matched pairs of initial lower-grade gliomas and recurrent tumors, most of which showed malignant progression when they recurred. Nearly half of IDH-mutant glioblastomas that had progressed from lower-grade gliomas exhibited characteristic partial DNA demethylation in previously methylated genomic regions of their corresponding initial tumors, which had the glioma CpG island methylator phenotype (G-CIMP). In these glioblastomas, cell cycle-related genes were upregulated, RB and PI3K-AKT pathway genes were frequently altered. Notably, bioinformatics analysis revealed that late-replicating domain was significantly enriched in the demethylated regions that were mostly located in non-regulatory regions, suggesting that the loss of DNA methylation during malignant transformation may involve mainly passive demethylation due to a delay in maintenance of methylation during accelerated cell division. Nonetheless, a limited number of genes including IGF2BP3, which potentially drives cell proliferation, were presumed to be upregulated due to demethylation of their promoter. Thus, cell proliferation was further promoted by passive demethylation in the promoter region of these oncogenic genes. Our data indicated that demethylation of the G-CIMP profile found in a subset of recurrent gliomas reflects accelerated cell divisions accompanied by malignant transformation. Oncogenic genes activated by such epigenetic change represent potential therapeutic targets.

Study JGAS000146

Heterogeneity of IKZF1 genomic alterations and risk of relapse in childhood B-cell precursor acute lymphoblastic leukemia

Purpose Genomic alterations of IKZF1 are common and associated with adverse clinical features in B-ALL, but the relationship between the type of IKZF1 alteration, disease subtype and outcome are incompletely understood. Patients and Methods We used transcriptome and genomic sequencing, and SNP microarray data to determine leukemia subtype and genomic alterations for 688 pediatric patients with B-ALL enrolled into St. Jude Total Therapy 15 and 16 studies. Results IKZF1 alterations were identified in 115 (16.7%) patients, commonly in BCR::ABL1 (78%) and CRLF2-rearranged, BCR::ABL1-like B-ALL (70%), and were associated with five-year cumulative incidence of relapse (CIR) of 14.8 ± 3.3% compared to 5.0 ± 0.9% for patients without any IKZF1 alteration (P < 0.0001). IKZF1 deletions of exon 4-7 (P = 0.0002), genomic IKZF1plus with any IKZF1 deletion (P = 0.006) or with focal IKZF1 deletion (P = 0.0007), and unfavorable genomic subtypes (P < 0.005) were independently adversely prognostic. Patients with both IKZF1 exon 4-7 deletion and unfavorable genomic subtype had a significantly increased risk of relapse (HR = 58.3; 95% CI, 11.9 – 285.4, P < 0.0001) whereas IKZF1 sequence mutations were not independently predictive of outcome. Conclusions Genomic IKZF1plus with any IKZF1 deletion, IKZF1 deletion of exon 4-7, and unfavorable subtype confer increased risk of relapse. The combination of unfavorable genomic subtype and IKZF1 deletion of exon 4-7 identified patients at greatest risk of relapse despite MRD-directed therapy. The type of IKZF1 alteration together with subtype are informative for risk stratification and predict response in patients with B-ALL.

Study EGAS50000000106

DNA methylation and the adverse metabolic outcomes of adiposity

Overweight and obesity affect ~1.5 billion people worldwide, and are major risk factors for type-2 diabetes (T2D), cardiovascular disease and related metabolic and inflammatory disturbances.1,2 Although the mechanisms linking adiposity to its clinical sequelae are poorly understood, recent studies suggest that adiposity may influence DNA methylation,3-6 a key regulator of gene expression and molecular phenotype.7 Here we use epigenome-wide association to show that body mass index (BMI, a key measure of adiposity) is associated with widespread changes in DNA methylation (187 genetic loci at P<1x10-7, range P=9.2x10-8 to 6.0x10-46; N=10,261 samples). Genetic association analyses demonstrate that the alterations in DNA methylation are predominantly the consequence of adiposity, rather than the cause. We find the methylation loci are enriched for functional genomic features in multiple tissues (P<0.05), and show that sentinel methylation markers identify gene expression signatures at 38 loci (P<9.0x10-6, range P=5.5x10-6 to 6.1x10-35, N=1,785 samples). The methylation loci identified highlight genes involved in lipid and lipoprotein metabolism, substrate transport, and inflammatory pathways. Finally, we show that the disturbances in DNA methylation predict future type-2 diabetes (relative risk per 1SD increase in Methylation Risk Score: 2.3 [2.07-2.56]; P=1.1x10-54). Our results provide new insights into the biologic pathways influenced by adiposity, and may enable development of new strategies for prediction and prevention of type-2 diabetes and other adverse clinical consequences of obesity.

Study EGAS00001001922

High-throughput Detection of Clinically Relevant Mutations in Archived Tumor Samples By Multiplexed PCR and Next Generation Sequencing

PURPOSE: Tailoring cancer treatment to tumor molecular characteristics promises to make personalized medicine a reality. However, reliable genetic profiling of archived clinical specimens has been hindered by limited sensitivity and high false positive rates. Here, we describe a novel methodology, MMP-seq, which enables sensitive and specific high-throughput, high content genetic profiling in archived clinical samples. EXPERIMENTAL DESIGN: We first validated MMP-seq’s technical performance in 66 cancer cell lines and a Latin square cross-dilution of known somatic mutations. We next characterized the performance of MMP-seq in 17 formalin-fixed paraffin embedded (FFPE) clinical samples using matched fresh frozen (FF) tissue from the same tumors as benchmarks. To demonstrate the potential clinical utility of our methodology, we profiled FFPE tumor samples from 73 endometrial cancer patients. RESULTS: We demonstrated that MMP-seq enabled rapid and simultaneous profiling of a panel of 88 cancer genes in 48 samples, and detected variants at frequencies as low as 0.4%. We identified DNA degradation and deamination as the main error sources and developed practical and robust strategies for mitigating these issues, and dramatically reduced the false positive rate. Applying MMP-seq to a cohort of endometrial tumor samples identified extensive, potentially actionable alterations in the PI3K and RAS pathways, including novel PIK3R1 hotspot mutations that may disrupt negative regulation of PIK3CA. CONCLUSIONS: MMP-seq provides a robust solution for comprehensive, reliable and high- throughput genetic profiling of clinical tumor samples, paving the way for the incorporation of genomic-based testing into clinical investigation and practice.

Study EGAS00001000674

Exome Sequencing Of 75 Individuals From Multiply Affected Coeliac Families

Coeliac disease is a highly heritable common autoimmune disease involving chronic small intestinal inflammation in response to dietary wheat. The human leukocyte antigen (HLA) region, and 40 newer regions identified by genome wide association studies (GWAS) and dense fine mapping, account for ~40% of the disease heritability. We hypothesized that in pedigrees with multiple individuals with coeliac disease rare [minor allele frequency (MAF) <0.5%] mutations of larger effect size (odds ratios of ~ 2 – 5) might exist. We sequenced the exomes of 75 coeliac individuals of European ancestry from 55 multiply affected families. We selected interesting variants and genes for further follow up using a combination of: an assessment of shared variants between related subjects, a model-free linkage test, and gene burden tests for multiple, potentially causal, variants. We next performed highly multiplexed amplicon resequencing of all RefSeq exons from 24 candidate genes selected on the basis of the exome sequencing data in 2,248 unrelated coeliac cases and 2,230 controls. 1,335 variants with a 99.9% genotyping call rate were observed in 4,478 samples, of which 939 were present in coding regions of 24 genes (Ti/Tv 2.99). 91.7% of coding variants were rare (MAF <0.5%) and 60% were novel. Gene burden tests performed on rare functional variants identified no significant associations (P<1x10-3) in the resequenced candidate genes. Our strategy of sequencing multiply affected families with deep follow up of candidate genes has not identified any new coeliac disease risk mutations.

Study EGAS00001001093

UK10K NEURO FSZNK

In the UK10K project we propose a series of complementary genetic approaches to find new low frequency/rare variants contributing to disease phenotypes. These will be based on obtaining the genome wide sequence of 4000 samples from the TwinsUK and ALSPAC cohorts (at 6x sequence coverage), and the exome sequence (protein coding regions and related conserved sequence) of 6000 samples selected for extreme phenotypes. Our studies will focus primarily on cardiovascular-related quantitative traits, obesity and related metabolic traits, neurodevelopmental disorders and a limited number of extreme clinical phenotypes that will provide proof-of-concept for future familial trait sequencing. We will analyse directly quantitative traits in the cohorts and the selected traits in the extreme samples, and also use imputation down to 0.1% allele frequency to extend the analyses to further sample sets with genome wide genotype data. In each case we will investigate indels and larger structural variants as well as SNPs, and use statistical methods that combine rare variants in a locus or pathway as well as single-variant approaches. This Finnish schizophrenia sample set has been collected from a population cohort using national registers. The entire sample collection consists of 2756 individuals from 458 families of whom 931 are diagnosed with schizophrenia spectrum disorder. Families outside Kuusamo (n=288) all had at least two affected siblings. All diagnoses are based on DSM-IV and for a large fraction of cases there is cognitive data.For further details/descriptions with regard to this data set please contact Tiina Paunio (tiina.paunio@thl.fi)

Study EGAS00001000119

UK10K NEURO ASD SKUSE

In the UK10K project we propose a series of complementary genetic approaches to find new low frequency/rare variants contributing to disease phenotypes. These will be based on obtaining the genome wide sequence of 4000 samples from the TwinsUK and ALSPAC cohorts (at 6x sequence coverage), and the exome sequence (protein coding regions and related conserved sequence) of 6000 samples selected for extreme phenotypes. Our studies will focus primarily on cardiovascular-related quantitative traits, obesity and related metabolic traits, neurodevelopmental disorders and a limited number of extreme clinical phenotypes that will provide proof-of-concept for future familial trait sequencing. We will analyse directly quantitative traits in the cohorts and the selected traits in the extreme samples, and also use imputation down to 0.1% allele frequency to extend the analyses to further sample sets with genome wide genotype data. In each case we will investigate indels and larger structural variants as well as SNPs, and use statistical methods that combine rare variants in a locus or pathway as well as single-variant approaches. This sample set of UK origin consists of clinically identified subjects with Autism Spectrum Disorders, mostly without intellectual disability (ie. Verbal IQs >70). The subjects represent children and adults with Autism, Asperger syndrome or Atypical Autism, identified according to standardized research criteria (ADI-algorithm, ADOS). A minority has identified comorbid neurodevelopmental disorders (e.g. ADHD). Family histories are available, with measures of broader phenotype in first-degree relatives.For further information on this cohort please contact David Skuse (d.skuse@ucl.ac.uk).

Study EGAS00001000114

UK10K_NEURO_MUIR

In the UK10K project we propose a series of complementary genetic approaches to find new low frequency/rare variants contributing to disease phenotypes. These will be based on obtaining the genome wide sequence of 4000 samples from the TwinsUK and ALSPAC cohorts (at 6x sequence coverage), and the exome sequence (protein coding regions and related conserved sequence) of 6000 samples selected for extreme phenotypes. Our studies will focus primarily on cardiovascular-related quantitative traits, obesity and related metabolic traits, neurodevelopmental disorders and a limited number of extreme clinical phenotypes that will provide proof-of-concept for future familial trait sequencing. We will analyse directly quantitative traits in the cohorts and the selected traits in the extreme samples, and also use imputation down to 0.1% allele frequency to extend the analyses to further sample sets with genome wide genotype data. In each case we will investigate indels and larger structural variants as well as SNPs, and use statistical methods that combine rare variants in a locus or pathway as well as single-variant approaches.The sample selection consists of subjects with schizophrenia (SZ), autism, or other psychoses all with mental retardation (learning disability). The samples were initially collected under the leadership of Walter J Muir (deceased), now with Prof. Blackwood, Dr McKechanie and Prof McIntosh as custodians. These subjects represent the intersection of severe forms of neurodevelopmental disorders, appear to have a higher rate of familiality of SZ than typical, and are likely to have more serious and penetrant forms of mutations.For further information on this cohort please contact Andrew McIntosh (andrew.mcintosh@ed.ac.uk).

Study EGAS00001000122

Chromatin immunoprecipitation linked to next-generation whole genome sequencing (ChIP-Seq) for H3K36me3 in paediatric high grade glioma cell lines KKNS4 and SF188 with and without a G34V mutation in H3F3A

Glioblastomas of children and young adults have a median survival of only 12-15months and are clinically and biologically distinct from histologically similar cancers in older adults1. They are defined by highly specific mutations in the gene encoding the histone H3.3 variant H3F3A2, occurring either at or close to key residues marked by methylation for regulation of transcription – K27 and G34. We performed chromatin immunoprecipitation linked to next-generation whole genome sequencing (ChIP-Seq) for H3K36me3 in order to test the hypothesis that, rather than total H3K36me3, the G34V mutation may instead result in differential binding of the trimethyl mark throughout the genome. Compared with H3F3A wild-type SF188 paediatric GBM cells, H3K36me3 was found to be significantly differentially bound in KNS42 cells at 5130 distinct regions of the genome corresponding to 156 genes. Concurrent whole genome DNA sequencing demonstrated that this was not confounded by copy number alterations. The cerebral hemispheric-specific G34 mutation drives a distinct expression signature through differential genomic binding of the K36 trimethylation mark (H3K36me3). The transcriptional program induced recapitulates that of the developing forebrain, and involves numerous markers of stem cell maintenance, cell fate decisions and self-renewal. Critically, H3F3A G34 mutations cause profound upregulation of MYCN, a potent oncogene which is causative of glioblastomas when expressed in the correct developmental context. This driving aberration is selectively targetable in this patient population by inhibiting kinases responsible for stabilisation of the protein.

Study EGAS00001001437

Quantification of chromosomal copy number aberrations by shallow whole-genome sequencing

Detection of DNA copy number aberrations by shallow whole-genome sequencing (WGS) faces many challenges including lack of completion and errors in the human reference genome, repetitive sequences, polymorphisms, variable sample quality, and biases in the sequencing procedures.Formalin-fixed paraffin-embedded (FFPE) archival material, the analysis of which is important for studies of cancer, presents particular analytical difficulties due to degradation of the DNA and frequent lack of matched reference samples. We present a robust, cost-effective WGS method for DNA copy number analysis that addresses these challenges more successfully than currently available procedures. In practice very useful profiles can be obtained with 0.1 fold genome coverage. We improve on previous methods by; first, implementing a combined correction for sequence mappability and GC content, and second, applying this procedure to sequence data from the 1000 Genomes Project in order to develop a blacklist of problematic genome regions. A small subset of these blacklisted regions were previously identified by ENCODE, but the vast majority are novel unappreciated problematic regions. Our procedures are implemented in a pipeline called QDNAseq. We have analyzed over 1,000 samples, most of which were obtained from the fixed tissue archives of over 25 institutions.We demonstrate that for most samples our sequencing and analysis procedures yield genome profiles with noise levels near the statistical limit imposed by read counting. The described procedures also provide better correction of artifacts introduced by low DNA quality than prior approaches, and better copy number data than high-resolution microarrays at substantially lower cost.

Study EGAS00001000642

UK10K_RARE_THYROID

In the UK10K project we propose a series of complementary genetic approaches to find new low frequency/rare variants contributing to disease phenotypes. These will be based on obtaining the genome wide sequence of 4000 samples from the TwinsUK and ALSPAC cohorts (at 6x sequence coverage), and the exome sequence (protein coding regions and related conserved sequence) of 6000 samples selected for extreme phenotypes. Our studies will focus primarily on cardiovascular-related quantitative traits, obesity and related metabolic traits, neurodevelopmental disorders and a limited number of extreme clinical phenotypes that will provide proof-of-concept for future familial trait sequencing. We will analyse directly quantitative traits in the cohorts and the selected traits in the extreme samples, and also use imputation down to 0.1% allele frequency to extend the analyses to further sample sets with genome wide genotype data. In each case we will investigate indels and larger structural variants as well as SNPs, and use statistical methods that combine rare variants in a locus or pathway as well as single-variant approaches.Two cohorts of subjects are being analysed: Individuals with Congenital Hypothyroidism (CH) due either to dysgenesis or dyshormonogenesis; Patients with Resistance to Thyroid hormone (RTH), a disorder characterized by elevated thyroid hormones and variable tissue refractoriness to hormone action. The CH cohort has been enriched for genetic aetiologies by recruiting cases that are familial, on a consanguineous background or syndromic. The RTH cohort consists of cases in which candidate gene analyses have been negative.For further information with regard to this cohort please contact Krishna Chatterjee (kkc1@medschl.cam.ac.uk).

Study EGAS00001000131

Evolution of a FLT3-TKD mutated subclone at meningeal relapse in acute promyelocytic leukemia (H021)

Here we report the case of an acute promyelocytic leukemia (APL) patient who, though negative for FLT3 mutations at diagnosis, developed isolated FLT3-TKD positive meningeal relapse, which, in retrospect, could be traced back to a minute bone marrow subclone present at first diagnosis. Initially, the 48-year old female diagnosed with high-risk APL had achieved complete molecular remission after standard treatment with all-trans retinoic acid (ATRA) and chemotherapy according to the AIDA protocol. 13 months after start of ATRA maintenance the patient suffered clinically overt meningeal relapse along with minute molecular traces of PML/RARA in the bone marrow. Following treatment with arsenic trioxide (ATO) and ATRA in combination with intrathecal cytarabine and methotrexate, the patient achieved a complete molecular remission in both cerebrospinal fluid (CSF) and bone marrow, which currently lasts for two years after completion of therapy. Whole exome sequencing and subsequent ultradeep targeted re-sequencing revealed a heterozygous FLT3-TKD mutation in CSF leukemic cells (p.D835Y, c.2503G>T, 1000/1961 reads (51%)), which was undetectable in the concurrent bone marrow sample. Interestingly, the FLT3-TKD mutated meningeal clone originated from a small bone marrow subclone present in a variant allele frequency of 0.4% (6/1553 reads) at initial diagnosis. This case highlights the concept of clonal evolution with a subclone harboring an additional mutation being selected as the “fittest” and leading to meningeal relapse. It also further supports earlier suggestions that FLT3 mutations may play a role for migration and clonal expansion in the CSF sanctuary site.H021

Study EGAS00001001848

Integrated clinical, whole genome, and transcriptome analysis of multisampled lethal metastatic prostate cancer

We report the first combined analysis of whole genome sequence, detailed clinical history, and transcriptome sequence of multiple prostate cancer metastases in a single patient (A21). Whole genome and transcriptome sequence was obtained from 9 anatomically separate metastases, and targeted DNA sequencing was performed in cancerous and noncancerous foci within the primary tumor specimen removed 5 years prior to death. Transcriptome analysis revealed increased expression of AR-regulated genes in liver metastases that harbored an AR p.L702H mutation, suggesting a dominant effect by the mutation despite being present in only 1 of an estimated 16 copies per cell. The metastases harbored several alterations to the PI3K/AKT pathway, including a clonal truncal mutation in PIK3CG and present in all metastatic sites studied. The list of truncal genomic alterations shared by all metastases included homozygous deletion of TP53, hemizygous deletion of RB1 and CHD1, and amplification of FGFR1. If the patient were treated today given this knowledge, use of second-generation androgen-directed therapies, cessation of glucocorticoid administration, and therapeutic inhibition of the PI3K/AKT pathway or FGFR1 receptor could provide personalized benefit. Three previously unreported truncal clonal missense mutations (ABCC4 p.R891L, ALDH9A1 p.W89R, and ASNA1 p.P75R) were expressed at the RNA level and assessed as druggable. The truncal status of mutations is critical for actionability, and can only be determined through analysis of multiple sites of metastasis. Our findings suggest that a large set of deeply analyzed cases could serve as powerful guide to more effective prostate cancer basic science and personalized cancer medicine clinical trials.

Study EGAS00001001659

Transcriptome Sequencing PPGL

RNA library preparation of samples with RNA Integrity Number (RIN) > 5.5 (median 7.1; range 5.6-8.9) was performed as described in the TruSeq Stranded mRNA Library Prep Kit (Illumina, RS-122-2101). Briefly, 0.7-1 µg total RNA PolyA+ fraction was purified and randomly fragmented, converted to double stranded cDNA and processed through subsequent enzymatic treatments of end-repair, dA-tailing, and ligation to adapters. Adapter-ligated library was completed by PCR with Illumina PE primers. The resulting purified cDNA library was applied to an Illumina flow cell for cluster generation and sequenced on an Illumina HiSeq2500 on a 51bp single-read format following manufacturer's protocols. cDNA libraries from FFPE tumors and low integrity RNA’s (RIN<5.5) from FF tumors (median 2.4; range 1-5.5) but % of fragments > 200 nucleotides higher than 20% (median 57.5; range 20-96) were prepared using QuantSeq 3’ mRNA-Seq Library Prep Kit FWD for Illumina (Lexogen, 015) with a UMI Second Strand Synthesis Module for QuantSeq FWD (Lexogen, 081), vendor’s protocol for low input/ low quality/ FFPE RNA using 200-500 ng of total RNA, according to availability, was used as starting material. PCR Add-on Kit for Illumina (Lexogen, 020) was used to adjust the library amplification number of cycles. Libraries were applied to an Illumina flow cell for cluster generation and sequenced on NovaSeq6000. Image analysis, per-cycle basecalling and quality score assignment was performed with Illumina Real Time Analysis software. Demultiplexing of BCL files to FASTQ format was performed with the bcl2fastq Software (Illumina).

Study EGAS00001006044

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