30 results for "study_type:"exome sequencing" AND repository:dbGaP"

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• Genetic Analysis of Limb Malformation Disorders: Freeman Sheldon Syndrome Exome Sequencing Study (LMD-FSS)

  The overall goal of this project is to investigate the etiology and pathogenesis of malformations (i.e., birth defects) of the limb, concentrating on abnormalities of limb patterning such as limb deficiency/duplications and multiple congenital contractures. The exome sequences of four unrelated individuals were obtained by massively parallel DNA sequencing. The three individuals were affected with Freeman Sheldon syndrome (OMIM: 193700).

  Study phs000204

• Genetic Analysis of Limb Malformation Disorders: Miller Syndrome Sequencing Study (LMD-MS)

  The overall goal of this project is to investigate the etiology and pathogenesis of malformations (i.e., birth defects) of the limb, concentrating on abnormalities of limb patterning such as limb deficiency/duplications and multiple congenital contractures. The exome sequences of two siblings and two unrelated individuals were obtained by massively parallel DNA sequencing. The four individuals were affected with Miller syndrome (OMIM: 263750). Additionally, the whole-genome sequences of a family of four were obtained with the method of Complete Genomics Incorporated (CGI). The two offspring were both affected with Miller syndrome and is the same sibling pair mentioned previously from whom exome sequences were also obtained.

  Study phs000244

• Next Generation Mendelian Genetics: Kabuki Syndrome

  The ultimate purpose of this research is to identify genes causing hereditary disorders. We are scaling a new approach to identify the candidate genes and gene mutations that underlie rare human Mendelian (a set of primary tenets relating to the transmission of hereditary characteristics from parent to child) diseases by using exome (protein coding segments of DNA) resequencing. The exome sequences of ten unrelated individuals with a diagnosis of Kabuki Syndrome (OMIM: 147920) were obtained by massively parallel DNA sequencing.

  Study phs000295

• Exome sequencing of autosomal recessive progressive external ophthalmoplegia (arPEO)

  Progressive external ophthalmoplegia (PEO) is an inherited mitochondrial disease that follows either autosomal dominant or recessive forms of inheritance (adPEO or arPEO). AdPEO is a genetically heterogeneous disease and several genes including POLG1 and C10orf2/Twinkle have been identified as responsible genes. On the other hand, POLG1 was the only established gene causing arPEO with mitochondrial DNA deletions. We previously reported a case of PEO with unidentified genetic etiology. The patient was born of a first-cousin marriage. Therefore, the recessive form of inheritance was suspected. To identify the disease causing variant in this patient, we subjected the patient's DNA to whole-exome sequencing and narrowed down the candidate variants using public data and runs of homozygosity analysis.

  Study phs000392

• Very Low Tumor Mutation Burden Identifies Inflamed Recurrent Glioblastomas Responsive to Cancer Immunotherapy

  A subset of available tumors (with matched blood) from patients enrolled in a phase I clinical trial testing a recombinant poliovirus, published by Desjardins et al. NEJM 2018 (PMID:29943666), were analyzed by whole exome sequencing and RNA-seq. It was discovered that low tumor mutation burden correlated with survival outcome, and also discovered that low tumor mutation burden correlated with higher inflammatory gene signatures by RNA-seq.

  Study phs002270

• Germline and Somatic Genetic Landscape of Pediatric Rhabdomyosarcoma

  Dynamic approaches that integrate population-based research and molecular biology are needed to explain the mechanisms underlying pediatric rhabdomyosarcoma (RMS) and to determine novel prevention strategies. RMS, the most common soft-tissue sarcoma in children and adolescents, has one of the poorest 5-year survival rates among all pediatric cancers (less than 65%). One of the strongest risk factors for RMS is having a cancer predisposition syndrome. The syndromes that are most commonly seen among those with RMS are Li-Fraumeni, neurofibromatosis type 1, Costello, Noonan, and DICER1. Based on smaller clinic-based studies, only about 7% of RMS cases are thought to be associated with the genes responsible for these syndromes. However, there have been no population-based assessments to support this estimate. Even in the most recent large-scale evaluations of germline mutations in predisposition genes among children with cancer, very few RMS cases were included (43 cases). Furthermore, no distinctions were made between the major histologic subtypes of RMS: embryonal (eRMS) and alveolar (aRMS), which display differences in terms of age distribution, incidence, and cytogenetics. For instance, nearly 80% of alveolar cases are driven by a chromosomal translocation between either PAX3 or PAX7 and FOXO1, whereas these fusions are not seen in embryonal cases. In fact, RMS research is shifting from categorization based on histology to fusion status (eRMS is overwhelmingly fusion-negative). Another limitation in previous studies has been the inability to evaluate the frequency of de novo germline mutations (DNMs) in cancer predisposition genes due to the absence of any well-characterized cohorts of RMS case-parent trios. Therefore, a major gap in our understanding of the role of cancer predisposition in pediatric RMS that limit translational impact is there have been no population-based assessments to determine the true impact of these mutations on pediatric RMS, which limits clinical sequencing guidelines and surveillance protocols in these children.Overall Project Strategy: The objective of this project is to advance our understanding of the relationship between cancer predisposition genes and pediatric RMS. Our central hypotheses are: 1) mutations in cancer predisposition genes are more common than expected in children with RMS; and 2) children with fusion-negative tumors have a higher burden of germline mutations than those with fusion-positive tumors. The framework for this study relies on >600 well annotated samples collected from newly diagnosed RMS patients and stored in the Children’s Oncology Group (COG) Biopathology Center.

  Study phs002304

• Lineage Plasticity and Immune Cell Heterogeneity Are Coordinately Dysregulated Through Changes in FOXA1 Expression in Bladder Cancers with Squamous Differentiation

  We performed whole exome sequencing (WES) of paired, macrodissected regions of urothelial carcinoma (UC), not otherwise specified (NOS-UC) and squamous differentiation (SqD) from 21 bladder tumors in which distinct and separable NOS-UC and SqD regions were present (total 42 exomes, in addition to matched normal exomes). Mean tumor mutational burden (TMB) was higher in the SqD versus the NOS-UC regions. Consistent with the higher TMB, the SqD regions also had a higher neoantigen burden than the patient-matched NOS-UC regions. The SqD regions also exhibited higher karyotypic complexity with a higher median ploidy relative to the paired NOS-UC regions. Phylogenetic analysis of the WES data confirmed that the morphologically distinct regions of all 21 tumors arose from a shared precursor with a median of 68 (range 16 – 852) non-synonymous mutations shared between the NOS-UC and SqD regions, and the overall data were indicative of early branched evolution. As whole exome sequencing did not identify a shared mutational alteration or genomic signature unique to the SqD or NOS-UC components, we therefore performed expression profiling of separable SqD and NOS-UC regions of 12 bladder tumors from the WES cohort with RNA quality sufficient for whole transcriptome RNA-sequencing (RNAseq, total of 24 regions). Based on centroid clustering analysis of expression data, all 12 regions of SqD were basal-squamous subtype based on the TCGA molecular classification schema. Notably, 8 of the NOS-UC regions were also basal-squamous subtype, with only four pairs exhibiting discordant transcriptional subtypes (three NOS-UC regions were luminal-infiltrated, one luminal-papillary). To better quantify differences in the transcriptional profiles of the paired NOS-UC and SqD regions, we used single sample gene set enrichment analysis (ssGSEA) to assess for enrichment of luminal or basal-squamous gene expression. ssGSEA analysis revealed that the SqD regions expressed higher levels of basal-squamous genes based on the BASE47 gene set and UPK/KRT gene sets; whereas the matched NOS-UC regions expressed higher levels of luminal genes. These differences in the levels of expression of basal and luminal genes were observed even in cases in which both the NOS-UC and SqD regions were basal-squamous subtype based the TCGA molecular classification schema. Exomes from eight patients in this study have previously been deposited in dbGaP: accession number phs001783 as part of the study "Exome Recapture and Sequencing of Prospectively Characterized Clinical Specimens From Cancer Patients".

  Study phs002357

• Parallel CRISPR Editing of Familial ALS Mutations Into a Healthy Control iPSC Line

  Induced pluripotent stem cells (iPSCs) provide a modeling system for human disease within the critical context of the human genome. CRISPR editing of iPSCs allows the construction of isogenic pairs where the cells have nearly identical genomes except for the desired edited change. Here, we used CRISPR editing on a healthy control line to generate three new isogenic iPSC lines that each contains a different familial amyotrophic lateral sclerosis (fALS) mutation (TARDBP[G298S/+], SOD1[G85R/+], and PFN1[G118V/+]). As controls for each mutation, we retained iPSC lines that went through the editing process but did not have the desired heterozygous mutation. We have produced high-throughput sequencing data from these isogenic lines in two different studies:(1) In “Human sensorimotor organoids derived from healthy and amyotrophic lateral sclerosis stem cells form neuromuscular junctions” (Pereira et al. 2021), we performed exome sequencing to confirm the absence of off-target CRISPR events. We also performed single-cell sequencing on sensorimotor organoids from a second healthy control iPSC line, which is deposited alongside the exome sequencing data.(2) In “iPSC Motor Neurons, But Not Other Derived Cell Types, Capture Gene Expression Changes in Postmortem Sporadic ALS Motor Neurons” (Held et al. 2023), we differentiated these isogenic lines into motor neurons, sensory neurons, cortical neurons, and astrocytes and then performed bulk RNA-sequencing. We then assessed similarities between fALS mutations, differences between cell types, and the capacity of iPSC modeling to capture differentially expressed genes in postmortem sporadic ALS motor neurons.

  Study phs002440

• Leveraging Extended Families for Cardiovascular Disease Genomic Discovery

  This study characterizes a large early onset atrial fibrillation family and identifies a rare causative mutation (R231H) in the KCNQ1 gene. The age of this mutation is ~5000 years, as estimated using IBD-coalescent methods. The geographic distribution and demographic history of the mutation is described. Induced pluripotent stem cell derived cardiomyocytes carrying the mutation have abbreviated action potential duration, indicating a gain-of-function. This data resource provides exome or whole genome sequencing data for six patients and RNA-seq data from the cardiomyocyte experiments. 

  Study phs002464

• Combined Targeting of CDK4/6 and HER2 Signaling in Orthotopic Patient-Derived Xenografts of HER2-Positive Breast Cancer Brain Metastases

  Patients with metastatic HER2-positive (HER2+) breast cancer will frequently develop brain metastases (BCBMs). Here, we report that p16INK4A, a tumor suppressor, is deficient in the majority of HER2+ BCBMs. Furthermore, p16INK4A deficiency, as measured by protein immunohistochemistry, can be a predictive marker associated with response to combined treatment with tucatinib and abemaciclib in our orthotopic patient-derived xenografts (PDXs) models of HER2+ BCBMs. Our findings provide the rationale for a biomarker-driven clinical trial of combined treatment with CDK4/6- and HER2-targeted agents for patients with HER2+ BCBM.  

  Study phs002482