3901 results for "*geneti*"

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• Rapid Evolution of a Skin Lightening Allele in Southern African KhoeSan

  The genetic architecture and polygenicity of skin pigmentation is explored in KhoeSan communities, including Nama individuals whose phenotype and genotype data are provided in this dataset. By pairing genotypes and quantitative spectrophotometric skin pigmentation phenotypes, we show that skin pigmentation is highly heritable in KhoeSan, yet known pigmentation loci only explains a small fraction of the phenotypic variance. Using genome-wide association analyses, we identified both canonical and non-canonical skin pigmentation loci. We show that this phenotype is more polygenic and complex than previously characterized. (Martin et al., Cell 2017. PMID: 29195075) Following up on the top associated signal with large effect size in the gene SLC24A5, we demonstrate that the canonical Eurasian nonsynonymous allele was introduced into KhoeSan via a recent migration ~2 kya and was under extremely strong selection. The derived allele was present at high frequency despite controlling for gene flow. With high-throughput sequences in the captured SLC24A5 region, we show that the most common derived haplotype is identical amongst Europeans, eastern African and KhoeSan. Using 4-population demographic simulations with selection, we show that the allele was introduced into the KhoeSan only 2,000 ya via a back-to-Africa migration and then experienced a selective sweep.

  Study phs001753

• Genetic measurement of memory B-cell recall using antibody repertoire sequencing

  We developed an improved high throughput sequencing approach to measure the quantities and sequences of the repertoire of antibody heavy chain RNA in a blood sample. Using this approach we analyzed the antibody repertoire in response to yearly vaccinations with influenza vaccines TIV and LAIV in healthy adults in two subsequent years. We determined vaccine response patterns specific to LAIV and TIV and found antibody sequences that were shared between two samples of the same individuals following influenza vaccination in subsequent years, thereby providing a genetic measurement of B-cell memory recall.

  Study phs000656

• OncoArray: Follow-up of Ovarian Cancer Genetic Association and Interaction Studies (FOCI)

  The Follow-up of Ovarian Cancer Genetic Association and Interaction Studies (FOCI) was one of five projects funded in 2010 as part of the NCI's Genetic Associations and Mechanisms in Oncology (GAME-ON) initiative (http://epi.grants.cancer.gov/gameon/). FOCI represents a collective effort that builds upon the strengths and history of collaboration inherent in the Ovarian Cancer Association Consortium (OCAC), a multidisciplinary group comprised of epidemiologists, genetic epidemiologists, statistical geneticists, molecular and cell biologists and clinicians that was formed in 2005. The other four funded GAME-ON projects were: the ColoRectal TransdisciplinaryStudy (CORECT), Elucidating Loci Involved in Prostate Cancer Susceptibility (ELLIPSE), Discovery, Biology, and Risk of Inherited Variants in Breast Cancer (DRIVE), and Transdisciplinary Research in Cancer of the Lung (TRICL). As part of our aim to discover, expand, and replicate ovarian cancer susceptibility loci, the GAME-ON projects and other consortia formed the OncoArray network (http://epi.grants.cancer.gov/oncoarray/) to develop and genotype a new custom genotyping array in large numbers of cancer cases and controls (over 400,000 samples) across multiple cancer types. The FOCI data includes over 50,000 ovarian cancer cases and controls genotyped with the Oncoarray at the Center for Inherited Disease Research (CIDR). Genotype calling and quality control procedures were performed under a standardized protocol across the Oncoarray consortium, and over 490,000 SNPs passed QC and are included under this dbGaP submission.

  Study phs001882

• Prediction of DNA Repair Inhibitor Response in Short Term Patient-Derived Ovarian Cancer Organoids

  In this study, 34 ovarian tumor organoids generated from 23 patients underwent paired DNA damage repair defect functional analyses and whole exome sequencing analysis to compare genetic mutational status to DNA repair functional capacity. 22 of the patients had high grade serous cancer and 1 of the patients had low grade serous cancer. A normal control, fresh parent tumor, and cells from the organoid culture generated from the parent tumor underwent whole exome sequencing analysis and the data from the sequencing analysis is provided here.

  Study phs001685

• Columbia University Study of Caribbean Hispanics with Familial and Sporadic Late Onset Alzheimer's disease

  Compared to Caucasians residing in the same community the incidence rate of Alzheimer's disease is approximately twice as high in Caribbean Hispanics. Moreover, Caribbean Hispanics represent a homogenous population with only a few founders. Replication of genetic associations in other ethnic groups provides supporting evidence that a putative gene is involved in the disease pathogenesis, and when different allelic variants within the same genes are associated with disease it can help to localize the pathogenic variant. SORL1 is an example of a candidate gene that was first identified in Hispanics and then confirmed in multiple ethnic and racial groups in a meta-analysis. For this project, we are genotyping 704 individuals in families multiply affected by Alzheimer's disease (166 families). These families were recruited in the United States, Puerto Rico and the Dominican Republic. In addition, we are genotyping 2491 individuals (960 patients with sporadic Alzheimer's disease and 1531 unrelated controls) phenotyped in a similar fashion totaling 3195 individuals. Both cohorts are followed at regular intervals of 18 to 24 months, and potential phenotypes available other than those related to Alzheimer's disease include body mass index, measured blood pressure, neurological history and examinations. More importantly, both studies are funded through 2014 and additional phenotypes could be added in successive waves. We propose a genome wide association (GWA) study of Alzheimer's disease and longitudinal changes in cognition and other age-related neurological and medical phenotypes. The goal will be to identify the chromosomal locations of genes underlying this disease and its related endophenotypes.

  Study phs000496

• The Mutational Landscape of CTCL and Sezary Syndrome

  Sezary syndrome is a leukemic and aggressive form of cutaneous T-cell lymphoma (CTCL) resulting from the malignant transformation of skin-homing central memory CD4+ T cells. To identify new genetic alterations involved in Sezary syndrome and CTCL transformation we performed whole-exome sequencing of tumor-normal sample pairs from 26 Sezary syndrome and 16 CTCL patients. These analyses revealed a distinctive pattern of somatic copy number alterations in Sezary syndrome including highly prevalent recurrent chromosomal deletions involving the TP53, RB1, PTEN, DNMT3A, and CDKN1B tumor suppressor genes. Mutation analysis identified a broad spectrum of somatic mutations involving key genes involved in epigenetic regulation (TET2, CREBBP, MLL3, BRD9, SMARCA4 and CHD3) and signaling, including mutations in MAPK1, BRAF, CARD11 and PRKG1 driving increased MAPK, NFKB and NFAT activity upon T-cell receptor stimulation. Collectively, our findings provide new insights into the genetics of Sezary syndrome and CTCL and support the development of personalized therapies targeting key oncogenically activated signaling pathways for the treatment of these diseases.

  Study phs000994

• Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA)

  Asthma is a complex disease where the interplay between genetic factors and environmental exposures influences susceptibility and disease prognosis. Asthmatics of African descent tend to have more severe asthma and more severe clinical symptoms than individuals of European ancestry. Advances in genetic and genomic technologies have revolutionized gene discovery for several complex diseases, but going to the next step in gene discovery for asthma among populations of African descent requires considering unique characteristics of this ethnic group, including adequate sample sizes and population stratification due to (European and African) admixture. Thus far, coverage of common genetic markers both in public databases and commercially available SNP chips has been inadequate to detect and measure genetic associations among African admixed populations. The aim of this study was therefore to catalog genetic diversity in populations of African descent, especially those whose ancestry reflects the African Diaspora in the Americas.

  Study phs001123

• PRE-DETERMINE: Biologic Markers and MRI SCD Cohort Study

  The PRE-DETERMINE Study is a prospective, multi-center study of 5,764 patients with a history of coronary artery disease (CAD) and documentation of either a prior myocardial infarction (MI) or mild to moderate left ventricular dysfunction (LVD) with left ventricular ejection fraction (LVEF) 35-50%. Patients were enrolled at 136 sites where information on baseline demographics, clinical characteristics, pertinent past medical history, lifestyle habits, cardiac test results, and medications were collected via electronic data capture. Electrocardiograms (ECG) along with a blood sample was also collected at baseline, sent to central laboratories, and stored for future analyses. Contrast-enhanced magnetic resonance imaging (CE-MRI) scans were collected on a subset of patients and analyzed. Enrollment closed in November 2013 and patients are now being followed centrally by the Clinical Coordinating Center via mail/phone to document interim non-fatal arrhythmic events and cause-specific mortality. Questionnaires that inquire about intervening implantable cardiac defibrillator (ICD) implantations, ICD therapies, cardiac arrest, and other pertinent cardiovascular endpoints are mailed to participants every six months, and follow-up telephone calls are made to non-responders. Study endpoints are being confirmed through review of medical records, interviews with next-of-kin, and autopsy reports, if available.The primary objective of PRE-DETERMINE is to determine whether biologic markers and ECGs can be utilized to advance sudden cardiac death (SCD) risk prediction in patients with coronary heart disease (CHD) and LVEF >30-35%. The overarching goal of the study is to identify a series of markers that alone or in combination specifically predict risk of arrhythmic death as compared to other causes of mortality among this at risk population of CHD patients with preserved LVEF> 30-35%. If biologic or ECG markers are identified that can specifically predict risk of ventricular arrhythmias, then these markers may serve as relatively inexpensive methods to identify those at risk. The public health impact of identifying markers could be quite substantial, leading to more efficient utilization of ICDs and advances in our understanding of mechanisms underlying SCD.Among the 95% of participants that provided a blood sample at baseline, genome wide genotyping using the Illumina Global Screening Array (GSA) has been performed. A total of 4,335 participants with European ancestry gave consent that allows genetic research and deposition of data into dbGaP.

  Study phs002940

• RNA sequencing, ATACseq, and TCR-seq of Tfh cells and CXCR5- CD4+ T cells in HIV infected lymph nodes

  The high dimensional analyses of CD4+ T cells in human lymph nodes are case-based analyses of the TCR repertoire, transcriptome, and epigenetic signatures of various CD4+ T cells in human lymph nodes. The study aims to determine clonal overlap between phenotypically distinct CD4+ T cells and the similarities between these populations on transcriptional and epigenetic levels. This study performs TCR repertoire sequencing using Molecular Identifier Clustering-based Immune Repertoire Sequencing (MIDCIRS). We found clonal overlap between a population of CXCR5- T cells and follicular helper T (Tfh) cells. We also show epigenetic and transcriptional similarities between CXCR5-PD-1+ T cells and Tfh cells. This study shares an overlapping set of donors with phs001548.

  Study phs001849

• Medulloblastoma exome sequence analysis

  Medulloblastomas are the most common malignant brain tumors in children. Identifying and understanding the genetic events that drive these tumors is critical for the development of more effective diagnostic, prognostic and therapeutic strategies. Recently, our group and others described distinct molecular subtypes of medulloblastoma based on transcriptional and copy number profiles. Here, we utilized whole exome hybrid capture and Illumina sequencing to identify somatic mutations across the coding regions of 92 primary medulloblastoma/normal pairs. Overall, medulloblastomas exhibit low mutation rates consistent with other pediatric tumors, with a median of 0.35 non-silent mutations per megabase. We identified twelve genes mutated at statistically significant frequencies, including previously known mutated genes in medulloblastoma such as CTNNB1, PTCH1, MLL2, SMARCA4 and TP53. Recurrent somatic mutations were identified in an RNA helicase gene, DDX3X, often concurrent with CTNNB1 mutations, and in the nuclear co-repressor (N-CoR) complex genes GPS2, BCOR, and LDB1, to our knowledge novel findings in medulloblastoma and all cancer. We show that mutant DDX3X potentiates transactivation of a TCF promoter and enhances cell viability in combination with mutant but not wild type beta-catenin. Together, our study reveals the alteration of Wnt, Hedgehog, histone methyltransferase and now N-CoR pathways across medulloblastomas and nominates the RNA helicase DDX3X as a component of pathogenic beta-catenin signaling in medulloblastoma. "Reprinted from 'MEDULLOBLASTOMA EXOME SEQUENCING UNCOVERS SUBTYPE-SPECIFIC SOMATIC MUTATION', with permission from Nature"

  Study phs000504