3308 results for "*geneti*"

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• Genomics of Blastic Plasmacytoid Dendritic Cell Neoplasm

  The goal of this study was to understand the genetic evolution and tumor phylogeny of blastic plasmacytoid dendritic cell neoplasm (BPDCN). BPDCN can present in patients with skin tumors of leukemia cells and no bone marrow or blood involvement, or alternatively, with both skin tumors and blood/bone marrow leukemia cells at the time of diagnosis. Here, we performed longitudinal sampling of tissues from patients with BPDCN, including both skin tumors and bone marrow, and in some cases serially at different time points through the course of diagnosis and treatment. These were studied by whole exome or whole genome DNA sequencing, comparing tumor samples to matched normal samples.

  Study phs003228

• 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.

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• Binding of Epstein Barr Virus EBNA2 Unifies Multiple Sclerosis Genetic Mechanisms

  This study is focused on multiple sclerosis (MS). MS is likely caused by a combination of genetic and environmental factors; however, the mechanisms contributing to these factors remain poorly understood. Epstein-Barr virus (EBV) in particular is a well-established environmental risk factor for MS. We have created a computational algorithm that systematically searches for common molecular mechanisms that might be impacted at multiple MS-associated loci. Using this algorithm, we have discovered that over 40% of MS-associated loci contain MS genetic variants that fall within regions of the human genome occupied by the EBV-encoded EBNA2 protein. The same MS-associated variants also impact gene expression levels of MS-associated genes in EBV-infected B cell lines. Our hypothesis is that allele-dependent binding of EBNA2 and its co-factors explains the allele-dependent risk at many MS genetic loci. Importantly, this hypothesis links the genetic associations of MS to the known molecular roles played by EBV and Notch signaling in disease processes.Subjects with and without MS were recruited into an Institutional Review Board (IRB)-approved protocol through the Cincinnati Autoimmune Registry and Repository. From each subject, DNA from peripheral blood was isolated for whole genome sequencing (WGS). These data will be used to identify genotype-dependent transcriptional regulation in cells assessed from patients and controls. This WGS data was deposited before the full integration of sequence data with other functional genomic data types.From each subject, 90 mL of blood is drawn for isolation of peripheral blood mononuclear cells from which primary B and T cells will be isolated. For each B cell isolation, an EBV-transformed B cell line will be derived.

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• Phenotyping and Therapeutic Approaches for Patients with Sellar/Suprasellar Disorders

  The goal of the study is to phenotype and genotype patients with rare hypothalamic and pituitary disorders and identify biomarkers of disease diagnosis, presentation, and progression. We are investigating genetic mechanisms of pituitary tumorigenesis as well as genomic/transcriptomic markers of disease presentation and severity. Patients with suspected or confirmed hypothalamic and/or pituitary disorders and their family members are recruited. Biospecimens including peripheral blood, urine, tumor tissue (as available), and/or stool are collected. Genetic analysis may include a variety of techniques including peripheral blood or tumor tissue targeted Sanger sequencing of one or few genes, peripheral blood or tumor tissue whole exome sequencing, and other as applicable.

  Study phs003245

• 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.

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• Therapeutic Genetics and Disease Modeling in LAMA2-CMD

  Merosin-deficient congenital muscular dystrophy (MDC1A) is an autosomal recessive disorder caused by mutations in the LAMA2 gene, resulting in a defective form of the extracellular matrix protein laminin-α2 (LAMA2). Individuals diagnosed with MDC1A exhibit progressive muscle wasting and declining neuromuscular functions. No treatments for this disorder are currently available. This study involves transcriptomic comparison analysis between MDC1A patient fibroblasts and healthy control fibroblasts to reveal changes in gene expression that contribute to LAMA2 congenital muscular dystrophy (LAMA2-CMD).

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• 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.

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• Genetic Analysis of Skin Cells

  Cutaneous squamous cell carcinoma (cSCC) is a form of skin cancer originating from keratinocytes in the skin. They have high mutation burdens, primarily driven by UV-radiation-induced DNA damage. The order in which mutations undergo selection during the evolution of cSCC is not known. A subset of cSCCs grow out of benign neoplasms called actinic keratoses. To better understand the evolution of cSCC, we identified cases of cSCCs adjacent to actinic keratoses. From these cases, we separately microdissected the surrounding normal skin, the actinic keratosis, and the cSCC, and we performed targeted DNA-sequencing on the tissue from each area. We reconstructed tumor phylogenies and performed spatial transcriptomics on the 10X FFPE Visium platform on a subset of cases. Collectively, these studies revealed the mutational and gene expression changes that arise during the evolution of cSCC.

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• Studies in the Pathogenesis of Systemic Capillary Leak Syndrome (SCLS, Clarkson Disease)

  Systemic capillary leak syndrome (Clarkson disease) is an ultra-rare disease of unknown etiology. Patients experienced transient and recurrent episodes of hypotensive shock and massive peripheral edema due to plasma extravasation, often precipitated by minor viral infections. Disease onset occurs most frequently in middle age, and there is no family history. More than 90% of patients with the disease have monoclonal gammopathy of unknown significance (MGUS). The goal of the study is to determine pathogenic mechanisms and identify genetic underpinnings of the disease. Toward this end, we performed whole genome sequencing (WGS).

  Study phs003261

• Maintenance of Brain Tumor Profile on Organotypic Brain Slice Culture (OBSC)

  We used uncultured tumor resection tissue from an NF2 mutation-driven grade II meningioma (MG-II) to investigate whether tumors engrafted onto organotypic brain slice cultures (OBSCs) maintained the genetic profile of the parent tumor. We prepared three groups of samples for whole exome sequencing (WES) from the same pool of dissociated MG-II tissue. Group HT is the original uncultured human tumor tissue (n = 3). Group CL is the parent tumor tissue expanded in standard in vitro cell culture until the minimum number of cells required for WES had grown. Because of initial cell loss and subsequent clonal expansion, this required six passages over the span of approximately one month (n = 3). Group BSHT is the uncultured tumor resection tissue engrafted onto OBSCs and subsequently dissected from the OBSCs at the conclusion of our standardized assay length (4 days; n = 4). WES analysis showed that tumor tissue engrafted onto OBSCs maintained a significant genetic resemblance to the parent tumor, while tumor tissue expanded in vitro displayed a distinctly different profile. Furthermore, the mutational profiles of all four BSHT biological replicates were markedly similar, indicating that each OBSC-engrafted tumor indeed contained a representative sample of the original patient tumor. A closer look at the hallmark NF2 mutations existing within all samples revealed that while all samples from the original tumor (HT1-3) and the OBSC-engrafted tumor (BSHT1-4) maintain the frame shift deletion at V24, this mutation was lost in all samples expanded in vitro (CL1-3) and replaced by mutations in other areas. Together, this data suggests that the rapid assay design and tumor-accommodating niche of our OBSC platform enables effective maintenance of the original patient tumor profile. The BBsplit algorithm from the BBtools suite was run on all samples to eliminate rat DNA contamination in the BSHT samples as well as to account for any biases that may result as a part of that process. Only the reads that were binned to the human reference were used for subsequent analysis. Reads were then mapped to the GRCh38 version of the human genome with BWA v0.7.17 and realigned together with ABRA2 v.23. Quality control was implemented using the GATK/Picard v4.1.7.0 toolkit. Somatic variants were called for each sample using the MuTect2 algorithm v4.1.7.0. Variants were merged into a single cohort variant call file and then converted to MAF via vcf2maf v1.6.21 tool. Variants were annotated using VEP v87. To identify mutations with potentially high biological impact, multiple filtering steps were applied to somatic mutation calling. First, we selected only the somatic variants that passed all filters from the MuTect2 FilterMutectCalls algorithm and second, only high/moderate impact (change coding) variants as defined by the VEP annotation were further analyzed. Over 1900 single nucleotide variants (SNVs) were detected across all samples. Figures that summarized the results were generated using maftools.

  Study phs003268