1758 results for "*geneti*"

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• WES analysis of a mixed cohort of pituitary tumors

  BACKGROUND: Sporadic pituitary adenomas are the second most common primary brain tumor, but their genetics remains incompletely understood. We performed deep DNA sequencing of 42 pituitary macroadenomas, including hormonally active and atypical adenomas. METHODS: Pituitary adenomas representative of a spectrum of histopathologic subtypes, primary and recurrent tumors, and MIB-1 proliferative indices were profiled. Whole-exome sequencing was performed on tumors and paired blood followed by analysis of somatic copy number alteration and mutation. RESULTS: On the whole, the tumors harbored a low rate of mutations, similar to other benign brain tumors. However, almost one-third (29%) exhibited somatic copy-number alterations across large fractions of the genome (up to 99%). Despite such widespread genomic disruption, these tumors had few focal events, which is atypical among highly-disrupted cancers. The other 71% of tumors formed a distinct molecular class, with somatic copy-number alterations involving less than 6% of the genome. Among the highly-disrupted group, 92% were functional or atypical null-cell adenomas, whereas 87% of the less-disrupted group were clinically non-functional adenomas. The only significantly recurrent events were arm-level losses of chromosomes 1, 2, 11, and 18. No significantly recurrent mutations or insertion/deletion events were identified, suggesting no genes are altered by exomic mutations in >15% of pituitary tumors. CONCLUSIONS: Genomic characterization of a large series of sporadic pituitary adenomas reveals two classes of tumor, based on genomic disruption from arm-level copy-number alterations, which associate with hormonal and histologic subtypes.

  Study EGAS00001001714

• Grey_Platelet_Syndrome__GPS_

  As part of the Bloodomics collaboration we have several categories of pedigrees with diseases/syndromes relevant to cardiovascular diseases (CVD). One such pedigree, Grey Platelet Syndrome (GPS) is a rare congenital bleeding disorder caused by a reduction or absence of alpha granules in platelets. Exome sequencing has been performed as part of a discovery program to ascertain potential causative variants of the clinical phenotype.

  Study EGAS00001000091

• PAS Pedigrees: Identification of novel genetic variants contributing to cardiovascular disease in pedigrees with premature atherosclerosis.

  The heritability of CVD has been estimated to be between 40 and 55%. Due to the low MAF, PAS-causing mutations cannot be identified by indirect genotyping because their presence cannot be inferred from common haplotypes, as has been done successfully to uncover common risk variants by GWAS. It has been shown by Ng et al that the causative gene for rare syndromes can be unequivocally identified by sequencing the exomes of only four cases and eight controls. We expect exome sequencing to result in a high number of mutations and non-causitive coding variants.

  Study EGAS00001000052

• Identification of cis- and trans-regulatory variation modulating microRNA expression levels in human fibroblasts

  MicroRNAs (miRNAs) are regulatory noncoding RNAs that affect the production of a significant fraction of human mRNAs via post-transcriptional regulation. Interindividual variation of the miRNA expression levels is likely to influence the expression of miRNA target genes and may therefore contribute to phenotypic differences in humans, including susceptibility to common disorders. The extent to which miRNA levels are genetically controlled is largely unknown. In this report, we assayed the expression levels of miRNAs in primary fibroblasts from 180 European newborns of the GenCord project and performed association analysis to identify eQTLs (expression quantitative traits loci). We detected robust expression for 121 miRNAs out of 365 interrogated. We have identified significant cis- (10%) and trans- (11%) eQTLs. Furthermore, we detected one genomic locus (rs1522653) that influences the expression levels of five miRNAs, thus unraveling a novel mechanism for coregulation of miRNA expression

  Study EGAS00000000056

• Procardis study on novel susceptibility genes for coronary artery disease (CAD)

  An increased level of Lp(a) lipoprotein has been identified as a risk factor for coronary artery disease that is highly heritable. The genetic determinants of the Lp(a) lipoprotein level and their relevance for the risk of coronary disease are incompletely understood. METHODS: We used a novel gene chip containing 48,742 single-nucleotide polymorphisms (SNPs) in 2100 candidate genes to test for associations in 3145 case subjects with coronary disease and 3352 control subjects. Replication was tested in three independent populations involving 4846 additional case subjects with coronary disease and 4594 control subjects. RESULTS: Three chromosomal regions (6q26-27, 9p21, and 1p13) were strongly associated with the risk of coronary disease. The LPA locus on 6q26-27 encoding Lp(a) lipoprotein had the strongest association. We identified a common variant (rs10455872) at the LPA locus with an odds ratio for coronary disease of 1.70 (95% confidence interval [CI], 1.49 to 1.95) and another independent variant (rs3798220) with an odds ratio of 1.92 (95% CI, 1.48 to 2.49). Both variants were strongly associated with an increased level of Lp(a) lipoprotein, a reduced copy number in LPA (which determines the number of kringle IV-type 2 repeats), and a small Lp(a) lipoprotein size. Replication studies confirmed the effects of both variants on the Lp(a) lipoprotein level and the risk of coronary disease. A meta-analysis showed that with a genotype score involving both LPA SNPs, the odds ratios for coronary disease were 1.51 (95% CI, 1.38 to 1.66) for one variant and 2.57 (95% CI, 1.80 to 3.67) for two or more variants. After adjustment for the Lp(a) lipoprotein level, the association between the LPA genotype score and the risk of coronary disease was abolished. CONCLUSIONS: We identified two LPA variants that were strongly associated with both an increased level of Lp(a) lipoprotein and an increased risk of coronary disease. Our findings provide support for a causal role of Lp(a) lipoprotein in coronary disease.

  Study EGAS00000000055

• RNA_Seq_in_Patients_with_Primordial_Dwarfism

  Transcriptome studies in patients with rare genetic diseases can potentially aid in theinterpretation of likely causal genetic variation through identification of altered transcriptabundance and/or structure. RNA-Seq is the most sensitive assay for both investigatingtranscript structure and abundanceThe primary aim of this pilot project is to investigate to what degree integrating exome-Seqand RNA-Seq data on the same individual can accelerate the identification of causal allelesfor rare genetic diseases. There are two main strands to this: (i) identifying which variantsdiscovered in exome-seq appear to be having a functional impact on transcripts, and (ii)identifying transcript outliers, especially among known causal genes, that may not necessarilyhave a causal variant identified from exome sequencing. The latter may identify the presenceof causal variants that lie far from coding regions (e.g. the formation of cryptic splice sitesdeep within introns, or loss of long range regulatory elements), which can be confirmed withfurther targeted genetic assays. Just over 50% of all disease-causing variants recorded in theHuman Gene Mutation Database (HGMD) affect transcript structure and abundance (e.g.nonsense SNVs, essential splice site SNVs, frameshifting indels, CNVs).This pilot project will study RNA from lymphoblastoid cell-lines from 12 patients withprimordial dwarfism syndromes, for 10 of these samples we have previously generate exomedata as part of our collaboration with the group of Prof Andrew Jackson. The two remainingsamples are positive controls where the causal mutation is known, and is known to affecttranscript structure and/or abundance.Primordial dwarfism is a prime candidate for these RNA-seq studies because all knowncausal mutations to date have key roles in DNA replication and thus, unsurprisingly, theproducts of the causal genes are typically ubiquitously expressed.Each RNA will be sequenced, with two technical replicates (independent RT-PCR and libraries) persample, and each replicate run in 1/2 of a HiSeq lane using 100bp paired reads. Samples preparation was as follows :The cells were grown to confluency, then pellets frozen at -80. RNA samples were prepared using the Qiagen RNeasy kit, then nanodropped and analyzed using the bioanalyzer to determine concentration and purity.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 EGAS00001000283

• The Genetic Analysis of multiple sclerosis

  We created these data in order to identify genetic variants associated with increased susceptibility to multiple sclerosis. Cases from many parts of the world were genotyped with the Illumina 660 chip along with Swedish controls. In our analysis we also used control data from the WTCCC2 common UK controls and from other published studies.

  Study EGAS00000000101

• Geographical structure and differential natural selection among North European populations

  European populations and epidemiological cohorts are of special significance in the current era of genomic research aiming to characterize the background of common human diseases. The genome sequence, detailed information of genetic variations between individuals, high-throughput molecular technologies and novel statistical strategies create new possibilities to define genetic and life-style risk factors behind common health problems. Studies of large population cohorts are needed to transform the genetic information to detailed understanding of the predisposing factors in diseases affecting most human populations. European twin cohorts provide a unique competitive advantage for investigations of the role of genetics and environment or life style in the etiology of common diseases. This project will apply and develop new molecular and statistical strategies to analyze unique European twin and other population cohorts to define and characterise the genetic, environmental and life-style components in the background of health problems like obesity, migraine, coronary heart disease and stroke, representing major health care problems worldwide.

  Study EGAS00000000033

• Lethal malformation syndrome

  Identification of the genetic basis of rare monogenic diseases can provide insights into disease mechanisms, biological pathways and potential therapeutic targets. Exome sequencing has proven to be a powerful, efficient strategy for the identification of the genes underlying rare Mendelian disorders. The genetic defect behind the lethal malformation syndrome under study is known in some cases and has proven useful in revealing the primary underlying defect. We have six typical unrelated families with no known mutation. The aim of this study is to identify the locus associated with this lethal malformation syndrome in these families using exome sequencing.

  Study EGAS00001000061

• The patterns and dynamics of genomic instability in metastatic pancreatic cancer

  Pancreatic cancer is an aggressive malignancy with a five-year mortality of 97–98%, usually due to widespread metastatic disease. Previous studies indicate that this disease has a complex genomic landscape, with frequent copy number changes and point mutations, but genomic rearrangements have not been characterized in detail. Despite the clinical importance of metastasis, there remain fundamental questions about the clonal structures of metastatic tumours, including phylogenetic relationships among metastases, the scale of ongoing parallel evolution in metastatic and primary sites, and how the tumour disseminates. Here we harness advances in DNA sequencing to annotate genomic rearrangements in 13 patients with pancreatic cancer and explore clonal relationships among metastases. We find that pancreatic cancer acquires rearrangements indicative of telomere dysfunction and abnormal cell-cycle control, namely dysregulated G1-to-S-phase transition with intact G2–M checkpoint. These initiate amplification of cancer genes and occur predominantly in early cancer development rather than the later stages of the disease. Genomic instability frequently persists after cancer dissemination, resulting in ongoing, parallel and even convergent evolution among different metastases. We find evidence that there is genetic heterogeneity among metastasis-initiating cells, that seeding metastasis may require driver mutations beyond those required for primary tumours, and that phylogenetic trees across metastases show organ-specific branches. These data attest to the richness of genetic variation in cancer, brought about by the tandem forces of genomic instability and evolutionary selection.

  Study EGAS00000000064