3924 results for "*geneti*"

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• Molecular Characterization of Hemimegalencephaly

  Somatic mutations, in which a fraction of the cells in the body have a deleterious mutation, are well recognized in cancer but only recently appreciated in neurological disease. Given a somatic mutation in a population of progenitor cells, all daughter cells inherit the mutation and are able to express the resultant phenotype as a function of the differentiation program. We recently identified the first de novo somatic mutations in the developing brain in the condition hemimegalencephaly (HME), a catastrophic focal epilepsy condition associated with a malformation of cerebral cortical development (MCD). HME is one of the most severe MCD syndromes, characterized by massive hamartomatous overgrowth of either of the two cerebral hemispheres. Cerebral hemispherectomy is a frequent treatment for refractory epilepsy, allowing the sampling of diseased tissue. By comparing DNA from a diseased brain with DNA from blood/saliva, we identified de novo somatic mutations in PIK3CA, AKT3 or MTOR, part of the mTOR pathway. Mutations were present in 8-40% of sequenced alleles in various brain regions sampled during surgery and in some codons known to activate proteins.• Population informationPatient samples were collected from multiple centers. The population is Caucasian and Hispanic• Molecular technologies employedWhole-exome sequencing• Principal findings of the studyWe were the first to describe mTOR-related and non-mTOR mutations causing hemimegalencephaly, and we described two-hit mutational models to explain the genetic pathogenesis of hemimegalencephaly

  Study phs002156

• Epigenetic Landscape of Human Parathyroids

  The goal of this study is to produce a comprehensive map of the chromatin landscape of human parathyroids. Data from 20 subjects with parathyroid adenoma causing primary hyperparathyroidism were used. For the sequencing platform, Illumina HiSeq 2000 with V3 high-output kits were used. For the data processing pipeline, reads were aligned to hg19 using Bowtie or BWA. For RNA-seq data, transcript levels were estimated per gene to RPKM using Cufflink. For ChIP-seq and ATAC-seq data, enrichment peaks were estimated compared to inputs or background using MACS2 after merging reads from replicates. For DNase-seq, significant peaks compared to background distribution were computed using Hotspot. For Hi-C data, significant interactions were detected using Juicer HiCCUPS and 5 kb resolution for the merged data from replicates. Chromatin states for parathyroids were computed using ChromHMM based on ChIP-seq profiles in parathyroids of H3K4me3, H3K4me1, H3K27ac, H3K36me3, H3K27me3 and H3K9me3 and the emission matrix from 18 states pre-trained in the Roadmap Epigenomics. Gene expression, binding positions of transcription factor, open chromatin regions, 3D-chromatin interaction, and chromatin states are submitted.

  Study phs003302

• Transcriptomic and Epigenetic Profiling of SCLC Patient Samples

  Small cell lung cancer (SCLC) is an aggressive disease with poor outcomes and limited treatment options. Recent studies have identified transcriptionally defined subsets of SCLC that may allow for the personalization of treatment. Here we use transcriptomic sequencing and methylation profiling (RRBS) of biopsy and cfDNA to develop a highly accurate DNA methylation-based classifier to distinguish SCLC subtypes. These results demonstrate the clinical feasibility of molecular subtyping of SCLC.

  Study phs003416

• Postmortem Analysis of the Caudate Nucleus in Schizophrenia

  This postmortem study examines genomic signatures (gene, transcript, exon, and exon-exon junction) in the caudate nucleus of individuals with or without psychiatric illnesses. We characterized genetic and epigenetic changes across the lifespan of 443 donor subjects, including 245 individuals without psychiatric illness, 154 individuals with schizophrenia, and 44 individuals with bipolar disorder. The subjects are 210 from African and 233 from European ancestries. Combining expression quantitative trait loci (eQTL) analysis, Mendelian randomization with the latest schizophrenia genome-wide association study (GWAS), transcriptome-wide association study (TWAS) and differential expression analysis, we identified many genes associated with schizophrenia risk, including potentially the dopamine D2 receptor short isoform. We found that antipsychotic medication has an extensive influence on caudate gene expression. We constructed caudate nucleus gene expression networks that highlight interactions involving schizophrenia risk. These analyses provide a resource for the study of schizophrenia and insights into risk mechanisms and potential therapeutic targets. There are 120 subjects in this study which are also present in the study phs000417.

  Study phs003495

• Genetic Causes of Congenital Anosmia

  The Genetic Causes of Congenital Anosmia study was designed to provide a list of candidate genes that are potentially causal for isolated congenital anosmia (ICA), a rare inherited disorder where individuals lack a sense of smell from birth in the absence of a known genetic syndrome (i.e. Kallman's syndrome). This study includes 193 participants from 18-87 years of age, divided into two cohorts: family and non-family. Genetic data from the family cohort was analyzed in a case-control family design to generate a list of 162 candidate genes for ICA. A targeted search for variants in this list of genes was then conducted in the non-family cohort to create a prioritized list of genes for further study. Ten unrelated families were recruited for the family cohort for a total of 52 participants, 25 of which had anosmia. The non-family cohort consisted of 141 anosmic individuals. 3 additional normosmic participants from incomplete families were collected, one of whom has a participating family member in the non-family cohort, and so has data provided here. Data collection was conducted remotely, resulting in 146 participants recruited from the United States, and 48 recruited internationally from ten different countries. Participants were interviewed for their anosmia status and to confirm that they had no known genetic syndromes. Participants also completed the University of Pennsylvania Brief Smell Identification Test (BSIT; Doty et al., 1984) to confirm their anosmic/normosmic status and provided a saliva sample for whole exome sequencing (WES). Participants who had family members with anosmia provided pedigree information via interview. Data submitted to dbGap include whole exome sequences from 194 individuals (163 anosmic) conducted with Illumina HiSeq2500 and Illumina NovaSeq next generation sequencing technologies. Family pedigree information for the 10 participating families and all participants in the non-family cohort who have non-participating anosmic family members was also included. Our goal was to provide a resource for further research into the genetics of isolated congenital anosmia and to aide in the understanding of this disorder, as well as human olfaction, in general. The WES data provided could be further analyzed for polygenic interactions, additional non-targeted analysis on the non-family cohort, or combined into databases of other anosmic populations for further gene targeting or selection.

  Study phs003328

• BarcUVa-Seq (Biology of Colorectal Cancer Risk Enhancers)

  This study was designed to generate a cohort of normal colon mucosal biopsies from the "average risk" population. Its primary aims included the development of an RNA-seq dataset of normal colon mucosal biopsies across three colon regions (ascending, transverse and descending). Further, we aimed to provide plausible prioritization to genetic components of colorectal cancer risk by employing methods such as expression quantitative trait loci analysis. In doing so, we provide a novel reference dataset for the study of colon cancer risk in the healthy colon epithelium. RNA-seq was performed in batches on an Illumina HiSeq 2500 (batch 1-7) or NovaSeq 6000 (batch 8) on a total of 463 samples. Matched genotyping data was generated on the Illumina OncoArray BeadChip. Phasing was carried out using Minimac 3 and imputation was performed using The Haplotype Reference Consortium panel on the Michigan Imputation Server.Genotype and RNA-seq data will be made available in dbGaP.

  Study phs003338

• NHLBI TOPMed - NHGRI CCDG: The GENetics in Atrial Fibrillation (GENAF) Study

  The Genetics in AF (GENAF) study enrolled individuals with early-onset lone AF before age 50 in Norway between 2009 and 2016. Early-onset was defined as diagnosis of AF before age 50. Lone AF was defined as AF in the absence of clinical or echocardiographic findings of cardiovascular disease, hypertension, metabolic or pulmonary disease. AF was documented in ECG. All participants underwent clinical examination, including ECG, echocardiography, and blood draw, from which DNA has been extracted. The study conforms to the principles of the Declaration of Helsinki and was approved by the Regional Ethics Committee (REK) in Norway (Protocol reference number: 2009/2224-5). All included patients gave written informed consent.

  Study phs001547

• 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

• Single Cell Genotypic and Phenotypic Analysis of Measurable Residual Disease in Acute Myeloid Leukemia

  Acute myeloid leukemia (AML) is a group of blood cancers with high mortality. Even though complete remission is often achieved, majority of the AML patients still relapse. Measurable residual disease (MRD), defined as the population of cancer cells which persists following chemotherapy, is responsible for AML relapse. Understanding the biology enabling MRD clones to resist therapy is necessary to guide the development of curative treatments more effectively. Discriminating residual leukemic clones, preleukemic clones, and normal precursors remains a challenge with current MRD tools. We developed a single cell MRD (scMRD) assay by combining flow cytometric enrichment of the targeted precursor/blast population with integrated single cell DNA sequencing (scDNA-seq) and immunophenotyping (Tapestri, Missionbio). The platform utilizes a custom amplicon panel covering 109 amplicons across 31 genes frequently mutated in AML and a panel of 42 oligo-conjugated antibodies against surface makers. We applied our scMRD assay to sequence 30 MRD samples (multiplexed into 6) from 29 AML patients to study the clonal architecture and protein correlation. In addition, 2 MRD samples were sequenced with scDNA+protein sequencing technology without enrichment or multiplexing. Five patients with AML at diagnosis were also sequenced with scDNA+protein sequencing technology without enrichment or multiplexing. In order to establish the sensitivity of our scMRD assay, we spiked AML cells into normal bone marrow cells. We sequenced 12 such spiked samples after multiplexing.

  Study phs003233

• Deterministic Evolution and Stringent Selection During Pre-Neoplasia

  The earliest events during human tumor initiation are poorly characterized but may hold clues as to how to detect and prevent malignancy. Here we model this occult process by engineering TP53 deficiency in primary human gastric organoids and performing experimental evolution in multiple clonally derived cultures over two years, thereby defining causal relationships between this common initiating genetic lesion and resulting phenotypes. TP53 loss induced progressive aneuploidy, including copy number alterations and complex structural variants that are common in established gastric cancers, and which accrued along a defined temporal order. Longitudinal single cell sequencing of TP53 deficient gastric organoids similarly indicates progression towards malignant transcriptional programs. Moreover, lineage tracing with expressed cellular barcodes revealed highly reproducible dynamics whereby initially rare subclones with shared transcriptional programs repeatedly attain clonal dominance. This powerful platform for experimental evolution reveals stringent selection and convergence at the genotypic and phenotypic levels in pre-malignant epithelial organoids, illuminating evolutionary constraints and barriers to malignant transformation.

  Study phs003249