218 results for ""option,com_discussions"+since"

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• Blood Group Genotypes and Phenotypes in Omani Blood Donors and Its Links With Susceptibility to Malaria

  The Omani population experienced endemic malaria prior to eradication in the late 1990's. Since malaria is known to be a strong selective pressure on the human genome, particularly at blood group associated loci, we aimed to understand how selective pressures from malaria may be affecting genetic variation at blood group loci. Blood samples were collected from 100 healthy, Omani blood donors. Serology testing for 10 clinically relevant blood groups and whole genome sequencing (WGS) to an average coverage of 16X were performed on all samples. Additionally, using the WGS data, genetic variants (SNPs and INDELs) were called for chromosomes 1 - 22 using GRCh38. We find signals of selection at the Plasmodium vivax associated locus, ACKR1 (the Duffy blood group), but not at any Plasmodium falciparum associated loci. We also characterized several previously undescribed blood group alleles in the Omani population affecting antigenic expression, mostly at the RHD, RHCE, and GYPB loci. The data available from this project include BAM files from 100 Omani samples aligned to GRCh38, per chromosome VCF files, and results from the serology tests for all 10 blood groups.

  Study phs003694

• Widespread DNA hypomethylation and differential gene expression in Turner syndrome

  Adults with 45,X monosomy (Turner syndrome) reflect a surviving minority since more than 99% of fetuses with 45,X monosomy die in utero. In adulthood 45,X monosomy is associated with increased morbidity and mortality, although strikingly heterogeneous with some individuals left untouched while others suffer from cardiovascular disease, autoimmune disease and infertility. The present study investigates the leukocyte DNAmethylation profile by using the 450K-Illumina Infinium assay and the leukocyte RNA-expression profile in 45,X monosomy compared with karyotypically normal female and male controls. We present results illustrating that genome wide X-chromosome RNA-expression profile, autosomal DNA-methylation profile, and the X-chromosome methylation profile clearly distinguish Turner syndrome from controls. Our results reveal genome wide hypomethylation with most differentially methylated positions showing a medium level of methylation. Contrary to previous studies, applying a single loci specific analysis at well-defined DNA loci, our results indicate that the hypomethylation extend to repetitive elements. We describe novel candidate genes that could be involved in comorbidity in TS and explain congenital urinary malformations (PRKX), premature ovarian failure (KDM6A), and aortic aneurysm formation (ZFYVE9 and TIMP1)

  Study EGAS00001002190

• Whole-genome sequencing of two probands with hereditary spastic paraplegia reveals novel splice-donor region mutation and known pathogenic mutation in SPG11

  Hereditary spastic paraplegias (SPG) are a group of heterogeneous neurodegenerative disorders, which are often presented with overlapping phenotypes such as progressive paraparesis and spasticity. To assist the diagnosis of SPG subtypes, next-generation sequencing is often used to provide supporting evidence. In this study, we report the case of two probands from the same family with SPG symptoms, including bilateral lower limbs weakness, unsteady gait, cognitive decline, dysarthria and slurring of speech since age of 14. Subsequent whole-genome sequencing revealed that the patients are compound heterozygous for mutations in SPG11 gene, including the paternally inherited c.6856C>T (p.Arg2286*) mutation and the novel maternally inherited c.2316+5G>A splice donor region mutation. Mutations in SPG11 are the common cause of autosomal recessive Spastic Paraplegia type 11. According to the ClinVar database, there are already 101 reported pathogenic mutations in SPG11 that are associated with SPG. To our knowledge, this is the first report of SPG11 mutations in our local population. Novel splice mutation identified in this study would enrich the catalog of SPG11 mutations, potentially leading to better genetic diagnosis of SPG.

  Study EGAS00001001849

• Biased allelic expression in human primary fibroblast single cells.

  The study of gene expression in mammalian single cells using genomic technologies now provides the possibility to investigate the patterns of allelic gene expression. We have used single-cell RNA sequencing to detect the allele-specific mRNA level in 203 single human primary fibroblast cells over 133,633 unique heterozygous single nucleotide variants (hetSNVs). We have observed that at the snapshot of analyses each cell contains mostly transcripts from one allele from the majority of genes; indeed 76.4% of the hetSNVs display stochastic monoallelic expression in single cells. Remarkably, adjacent hetSNVs exhibit haplotype consistent allelic ratio; in contrast distant sites located in two different genes are independent of the haplotype structure. Moreover, the allele-specific expression in single cells correlated with the abundance of the cellular transcript. We observed that genes expressing both alleles in majority of the single cells at a given time point are rare and enriched in highly expressed genes. The relative abundance of each allele in a cell is controlled by some regulatory mechanisms since we observed related single-cell allelic profiles according to genes. Overall, these results have direct implications in cellular phenotypic variability.

  Study EGAS00001001009

• PATL2 is a key actor of oocyte maturation whose invalidation causes infertility in women and mice

  The genetic causes of oocyte meiotic deficiency (OMD), a form of primary infertility characterised by the production of immature oocytes, remain largely unexplored. Using whole exome sequencing, we found that 26% of a cohort of 23 subjects with OMD harboured the same homozygous nonsense pathogenic mutation in PATL2, a gene encoding a putative RNA-binding protein. Using Patl2 knockout mice, we confirmed that PATL2 deficiency disturbs oocyte maturation, since oocytes and zygotes exhibit morphological and developmental defects respectively. PATL2's amphibian orthologue is involved in the regulation of oocyte mRNA as a partner of CPEB. However, Patl2's expression profile throughout oocyte development in mice, alongside colocalisation experiments with Cpeb1, Msy2 and Ddx6 (three oocyte RNA-regulators) suggest an original role for Patl2 in Mammals. Accordingly, transcriptomic analysis of oocytes from WT and Patl2-/- animals demonstrated that in the absence of Patl2, expression levels of a select number of highly relevant genes involved in oocyte maturation and early embryonic development are deregulated. In conclusion, PATL2 is a novel actor of mammalian oocyte maturation whose invalidation causes OMD in humans.

  Study EGAS00001002903

• Next Generation Sequencing in an IBD Pedigree Whole Genome Data

  In 2009 we identified a four-generation family with over 700 members and 41 affected with Crohn's disease (CD). At the time we sequenced the exome of 6 affected individuals but did not identify any coding variants which appear to explain the high prevalence of disease. Since then we have collected DNA from a large number of additional family members, genotyped linkage arrays on the entire family to refine genomic regions shared by identity by descent and genotyped affected and unaffected members at known CD risk loci identified by Genome Wide Association Studies (GWAS). These analyses have confirmed that a significant unexplained excess of disease remains after accounting for all known genetic factors, and that several regions of the genome are shared by a large fraction of affected individuals. We therefore perform whole genomes sequencing from 8 individuals which will allow us to impute the complete sequence of nearly all the members of the two largest and most severely affected branches of the family.

  Dataset EGAD00001000399

• Human Microbiome Project Demonstration Study of Cutaneous Microbiome in Psoriasis

  Psoriasis, a highly prevalent disease of humans of unknown cause, is a chronic inflammatory disorder primarily involving skin, with distinctive clinical characteristics. With the newly developed tools that facilitate microbiome research, it now is possible to assess whether the cutaneous microbiome plays a role in the pathogenesis of this disorder. Preliminary data from our studies suggest that the cutaneous microbiome in psoriasis is complex and possibly different from normal. To deal with this complexity, we propose to examine the cutaneous microbiome in relation to psoriasis with explorations at several taxonomic and informatic levels. Our overall objective is to examine how changes in the normal cutaneous microbiome contribute to the pathogenesis of psoriasis. Since causality is complex and often difficult to prove, and beyond the scope of this RFP, our overall hypothesis is that there are alterations in the cutaneous microbiome in areas of skin affected by psoriasis in comparison with the range observed in clinically unaffected areas, or in healthy persons. We also hypothesize that the characteristics of the microbiome may affect clinical responses to the immunomodulatory agents used to treat psoriasis. An alternative hypothesis is that effective treatment of psoriasis with systemic immunomodulatory agents will not substantially affect the disordered microbial ecosystem. Such observations would provide evidence for the roles of the microbiota in this disorder. Since an important consideration in microbiome research is the optimal level (e.g. phylum, genus, species, strain, gene) at which to examine a scientific question, and we are not yet certain what are the optimal levels for psoriasis, this also will be examined. Our studies of psoriasis should allow development of both approaches and tools that will have general utility for Microbiome research. To test our hypothesis, we propose the following specific aims: 1) To understand the cutaneous microbiome species composition overlaying psoriatic lesions; 2)To investigate differences in metagenome content for psoriatic lesions compared to normal skin; 3) To identify differences in the transcriptional profiles of the microbiome and the host between normal skin and psoriatic lesions using high-throughput sequencing; and 4) To estimate the effects of systemic immunomodulatory therapy for psoriasis on microbiome composition. In total, these studies should help us understand the role of the microbiome in psoriasis pathogenesis. We sought to characterize and compare the cutaneous microbiota of psoriatic lesions (lesion), unaffected contralateral skin from psoriatic patients (normal), and similar skin loci in matched healthy controls (control) in order to discern patterns that govern skin colonization and their relationship to clinical diagnosis. Using high-throughput 16S rRNA sequencing, we assayed the cutaneous bacterial communities of 51 matched triplets and characterized these samples using community data analysis techniques.

  Study phs000251

• Relationship between low LDL cholesterol concentrations not due to statin therapy and risk of type 2 diabetes: a US-based cross-sectional observational study using electronic medical records

  Lipid lowering therapy using HMG-CoA reductase inhibitors (statins) is associated with an approximately 9-12% increase in the risk of new-onset type 2 diabetes (T2DM). The risk of diabetes could be increased by statins directly; however, genetic approaches have also implicated low LDL cholesterol (LDL-C) concentrations as a risk factor for T2DM. Mendelian randomization studies using functional variants in both HMGCR (GeneID:3156) and PCSK9 (GeneID:255738) genes found a higher risk of T2DM in individuals with variants associated with lower LDL-C concentrations. Since PCSK9 and HMGCR are involved in lipid metabolism through distinct molecular pathways, the altered glycemic effect associated with variants in both genes is likely to be the result of their common effect on LDL-C concentrations. Despite the findings from statin clinical trials and genetic studies, there is little direct evidence implicating low LDL-C concentrations with increased risk of T2DM. Individuals who have very low LDL-C concentrations not due to lipid lowering therapy can provide insights into the relationship between low LDL-C concentrations and T2DM. Here, we used de-identified electronic health records (EHRs) to test the hypothesis that low LDL-C concentrations are associated with T2DM.

  Study phs001588

• Sporadic Amyotrophic Lateral Sclerosis (ALS): Parent-Offspring and Twin Sequencing Study

  Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that affects the nerves in the brain and spinal cord, leading to muscle weakening and eventual paralysis and death. Ten percent of ALS cases are thought to be familial while the majority of cases are sporadic and the causative factors unknown. Dr. Roger Pamphlett of the University of Sydney has collected a unique cohort of consented trios where the child has ALS but the parents are unaffected. Since the age of onset is so late, it is very difficult to obtain this kind of trio. We have performed whole exome sequencing on these trios to identify de novo and recessive germline variants associated with sporadic ALS. In addition, Dr. Pamphlett has assembled a collection of consented discordant monozygotic twins, where one twin has ALS and the other is unaffected. We performed whole genome sequencing on these twin pairs to identify postzygotic variants that may contribute to sporadic ALS susceptibility. Finally, we have the opportunity to compare the sequence and gene expression in affected and unaffected tissues from blood, brain and/or spinal cord samples from consented ALS patients to look for somatic mutations or gene expression changes that may further our understanding of the disease.

  Study phs000831

• Cardiovascular Health Study (CHS) - Imaging

  The Cardiovascular Health Study (CHS) is a prospective study of risk factors for development and progression of coronary heart disease (CHD) and stroke in people aged 65 years and older. The 5,888 study participants were recruited from four U.S. communities and have undergone extensive clinic examinations for evaluation of markers of subclinical cardiovascular disease. The original cohort, enrolled in 1989-90, totaled 5,201 participants. A supplemental cohort of 687 predominantly African-American participants was enrolled in 1992-93. Clinic examinations were performed at study baseline and at annual visits through 1998-1999, and again in 2005-2006. Examination components included medical and personal history, medication inventory, ECG, blood pressure, anthropometry, assessment of physical and cognitive function, and depression screening. Other components done less frequently included phlebotomy, spirometry, echocardiography, carotid ultrasound, cerebral magnetic resonance imaging, measurement of ankle-brachial index and retinal exam. Participants were contacted by telephone annually between exams to collect information about hospitalizations and potential cardiovascular events. Since 1999, participants have been contacted every six months by phone, primarily to identify cardiovascular events and to assess physical and cognitive health. Standard protocols for the identification and adjudication of events were implemented during follow-up. The adjudicated events are myocardial infarction, angina, heart failure (HF), stroke, transient ischemic attack (TIA), claudication, and mortality.

  Study phs003639