4004 results for "*geneti*"

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• Human islet 3D chromatin maps provide insights into type 2 diabetes

  The transcriptional output of each cell type is controlled by thousands of enhancers, many of which contain genetic risk variants for common diseases such as type 2 diabetes (T2D). To gain insight into how enhancer variation influences diabetes risk, we created promoter capture Hi-C maps in human pancreatic islets. This linked diabetes-associated islet enhancers with their target genes, often located hundreds of kilobases away. We identified hubs that show spatial and functional connections between enhancersand target genes related to islet function and diabetes. We demonstrate that genetic variants distributed across hub enhancers have a major impact on T2D heritability, and use this knowledge to identify individuals in whom islet regulatory variation has a prominent role in T2D risk. Our results demonstrate the importance of 3D chromatin architecture for molecular interpretation of T2D genetic association signals, and define genomic spaces that harbor a distinct component of the T2D polygenic burden.

  Study EGAS00001002917

• Integrated genetic and epigenetic analysis defines novel molecular clusters in rhabdomyosarcoma

  Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood. To unravel the genetic/epigenetic basis of RMS, we studied 60 RMS cases using whole exome/transcriptome sequencing, copy number (CN) profiling, and DNA methylome analysis. Based on DNA methylation patterns, RMS was clustered into 4 distinct subtypes, which exhibited remarkable correlation with mutation/CN profiles, histological phenotypes, and clinical behaviors. A1 and A2 subtypes, especially A1, largely corresponded to alveolar histology with frequent PAX3/7 fusions and alterations in cell cycle regulators. In contrast, mostly showing embryonal histology, both E1 and E2 subtypes were characterized by high frequency of CN alterations and/or allelic imbalances, FGFR4/RAS/AKT pathway mutations and PTEN mutations/methylation and in E2, also by p53 inactivation. Despite generally poor prognosis in RMS, patients in E1 cluster exceptionally showed excellent prognosis. Our results highlight the close relationship between DNA methylation status and gene mutations and biological behavior in RMS.

  Study EGAS00001000884

• Genetics_and_Networks_of_Congenital_Heart_Defects

  Exome sequencing of families with Congenital Heart Defects of diverse sub-phenotypes. Comprises both parent-offspring trios for sporadic cases and multiplex families. Collaboration with David Brook, University of Nottingham. Funded by the British Heart Foundation.

  Study EGAS00001000762

• 503 genotypes from Inner Asia used in 'Close inbreeding and low genetic diversity in Inner Asian human populations despite geographical exogamy' publication

  Inner Asia is particularly interesting to understand human history and evolution, as two groups presenting contrasting cultural traits (notably their language, their social organisation and matrimonial system) cohabit. We sampled 503 individuals from these two groups, belonging to 17 populations from 11 distinct ethnic groups (AltaiKizhi, Kazakh, Khakas, Kyrgyz, Mongolian, Shore, Tajik, Telengit, Tubalar, Turkmen and Uzbek). The samples were then genotyped with 5 different DNA-arrays and, after quality-control, the 253,532 autosomal SNPs present in all the arrays were merged together in the present dataset.

  Study EGAS00001002951

• To determine the mutational impact of the in vitro culture, clonal human adult and pluripotent stem cell lines were subjected to a second clonal step after 3 months of culture. These subclones were whole genome sequenced to identify all the mutations that accumulated during the 3 month culture period.

  Genetic changes acquired during culture pose a potential risk for the successful application of stem cells. To assess the risk of in vitro expansion on mutation accumulation we have performed whole genome sequencing of clonally expanded human induced pluripotent stem cells (iPS cells) and adult stem cells (ASCs) to identify all mutations that accumulated over a fixed culture period. We find that ASCs acquire more single nucleotide variants (SNVs) and indels per population doubling than the iPS cells. When compared with ASCs, iPS cells are more vulnerable to mutations in genes and promoters. Mutational analysis revealed a clear in vitro induced mutational signature that is irrespective of stem cell type. This in vitro signature is characterized by C to G transversions that are probably caused by oxidative stress. Additionally, we observed stem cell specific mutational signatures and differences in transcriptional strand bias, indicating differential activity of DNA repair mechanisms between stem cell types in culture. In conclusion, in vitro culture induces mutation accumulation in iPS cells and ASCs. Culture under low-oxygen tension may help to reduce the number of culture-induced mutations.

  Study EGAS00001002955

• Deciphering Developmental Disorders (DDD)

  The Deciphering Developmental Disorders (DDD) study is a research collaboration between the Wellcome Trust Sanger Institute, the NHS clinical genetics services and families across the UK and Ireland. The project aims to improve the diagnosis of children with developmental disorders by using high-resolution microarray and massively parallel sequencing technologies on 12,000 children and their parents. Genetic changes that explain the child's symptoms will be displayed in the DECIPHER database (https://decipher.sanger.ac.uk). Extended datasets generated by the DDD project will be available in the European Genome-Phenome Archive with access carefully managed by a Data Access Committee.

  Study EGAS00001000775

• PSCP_bisulphite_analysis_in_hESCs

  Many studies over the past 10 years, culminating in the recent report of the International Stem Cell Initiative (ISCI, 2011) have shown that hPSC acquire genetic and epigenetic changes during their time in culture. Many of the genetic changes are non-random and recurrent, probably because they provide a selective growth advantage to the undifferentiated cells. Some are shared by embryonal carcinoma cells, the malignant counterparts of ES cells. The origins of these growth advantages are poorly understood, but may come from altered cell cycle dynamics, resistance to apoptosis or altered patterns of differentiation. Less is known about the nature and consequences of epigenetic changes, but it is likely that these similarly affect hPSC behaviour; e.g., enhanced expression of DLK1, an imprinted gene, is associated with altered hPSC growth (Enver et al 2005). Inevitably, these genetic and epigenetic changes will impact on our ability to use hPSC for regenerative medicine, either because malignant transformation of the undifferentiated cells or their differentiated derivatives to be used for transplantation compromises safety, or because they impede the function of those differentiated derivatives, or because they affect the efficiency with which the undifferentiated cells can be expanded and differentiated into desired cell types. Focusing initially upon the existing clinical grade hESC lines, later moving to iPSC, we will Consolidate and extend knowledge of the rate, type and functional impact of the genetic variations that occur during hPSC culture. We will use whole genome and exome sequencing as well as SNP arrays, together with clonal analysis and other cytogenetics techniques. Common changes will be compared with those found in the normal human population, at low frequency in the original cell population or observed during iPSC generation in the HIPSCI project currently based at the WTSI. These studies will provide a better understanding of the range of genetic changes that occur in hPSC beyond the CNVs already identified. In conjunction with cancer genome resources and expertise at WTSI, bioinformatic analyses of these hPSC data will allow us to assess potential impact on hPSC behaviour pertinent to applications in regenerative medicine, notably the likelihood that specific changes arising in undifferentiated PSC cultures may be associated with potential malignant transformation of differentiated progeny. 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 EGAS00001001625

• Whole-Genome and Epigenomic Landscapes of Etiologically Distinct Subtypes of Cholangiocarcinoma

  Cholangiocarcinoma (CCA) is a hepatobiliary malignancy exhibiting high incidence in countries with endemic liver-fluke infection. We analyzed 489 CCAs from 10 countries, combining whole-genome (71 cases), targeted/exome, copy-number, gene expression, and DNA methylation information. Integrative clustering defined 4 CCA clusters-fluke-positive CCAs (clusters 1/2) are enriched in ERBB2 amplifications and TP53 mutations; conversely, fluke-negative CCAs (clusters 3/4) exhibit high copy-number alterations and PD-1/PD-L2 expression, or epigenetic mutations (IDH1/2, BAP1) and FGFR/PRKA-related gene rearrangements. Whole-genome analysis highlighted FGFR2 3' untranslated region deletion as a mechanism of FGFR2 upregulation. Integration of noncoding promoter mutations with protein-DNA binding profiles demonstrates pervasive modulation of H3K27me3-associated sites in CCA. Clusters 1 and 4 exhibit distinct DNA hypermethylation patterns targeting either CpG islands or shores-mutation signature and subclonality analysis suggests that these reflect different mutational pathways. Our results exemplify how genetics, epigenetics, and environmental carcinogens can interplay across different geographies to generate distinct molecular subtypes of cancer.SIGNIFICANCE: Integrated whole-genome and epigenomic analysis of CCA on an international scale identifies new CCA driver genes, noncoding promoter mutations, and structural variants. CCA molecular landscapes differ radically by etiology, underscoring how distinct cancer subtypes in the same organ may arise through different extrinsic and intrinsic carcinogenic processes.

  Study EGAS00001001653

• Genomic profiling of paediatric glioma cell lines

  Although paediatric gliomas resemble their adult counterparts in many ways, there appear to be distinct clinical and biological differences. One important factor hampering the development of new targeted therapies is the relative lack of cell lines derived from childhood glioma patients, as it is unclear whether the well-established adult lines commonly used are representative of the underlying molecular genetics of childhood tumours. We have carried out a detailed molecular profiling of paediatric glioma cell lines KNS42, SF188, UW479, RES259 and RES186.

  Study EGAS00001003006

• Exome sequencing of stroke cases with good or bad recovery three months after stroke

  With the aim to identify rare genetic variation involved in stroke recovery, this is a pilot study on extreme phenotypes of good and bad recovery. Exome sequencing was performed on 41 and 49 samples in the bad and good recovery subset, respectively. Rare Variant association Analysis was performed on the exome sequencing results.

  Study EGAS00001003463