Publications by authors named "Amanda Dobbyn"

Schizophrenia (SCZ) is a chronic mental illness and among the most debilitating conditions encountered in medical practice. A recent landmark SCZ study of the protein-coding regions of the genome identified a causal role for ten genes and a concentration of rare variant signals in evolutionarily constrained genes. This recent study-and most other large-scale human genetics studies-was mainly composed of individuals of European (EUR) ancestry, and the generalizability of the findings in non-EUR populations remains unclear.

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Phenome-wide association studies identified numerous loci associated with traits and diseases. To help interpret these associations, we constructed a phenome-wide network map of colocalized genes and phenotypes. We generated colocalized signals using the Genotype-Tissue Expression data and genome-wide association results in UK Biobank.

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Background: Anorexia nervosa (AN) is a psychiatric disorder with complex etiology, with a significant portion of disease risk imparted by genetics. Traditional genome-wide association studies (GWAS) produce principal evidence for the association of genetic variants with disease. Transcriptomic imputation (TI) allows for the translation of those variants into regulatory mechanisms, which can then be used to assess the functional outcome of genetically regulated gene expression (GReX) in a broader setting through the use of phenome-wide association studies (pheWASs) in large and diverse clinical biobank populations with electronic health record phenotypes.

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Article Synopsis
  • Bipolar disorder has a genetic basis and complex causes; a large study compared nearly 42,000 bipolar patients with over 371,000 healthy controls, revealing 64 genomic regions linked to the disorder.
  • The findings showed that risk-related genes are heavily associated with brain functions, particularly in areas like the prefrontal cortex and hippocampus, and they include targets for various medications.
  • The research also distinguished between bipolar disorder types I and II, revealing a close genetic relationship and highlighting 15 specific genes that could lead to new treatment options and further investigations.
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The clinical impact of rare loss-of-function variants has yet to be determined for most genes. Integration of DNA sequencing data with electronic health records (EHRs) could enhance our understanding of the contribution of rare genetic variation to human disease. By leveraging 10,900 whole-exome sequences linked to EHR data in the Penn Medicine Biobank, we addressed the association of the cumulative effects of rare predicted loss-of-function variants for each individual gene on human disease on an exome-wide scale, as assessed using a set of diverse EHR phenotypes.

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Adverse side effects often account for the failure of drug clinical trials. We evaluated whether a phenome-wide association study (PheWAS) of 1167 phenotypes in >360,000 U.K.

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Joint analysis of multiple traits can result in the identification of associations not found through the analysis of each trait in isolation. Studies of neuropsychiatric disorders and congenital heart disease (CHD) which use de novo mutations (DNMs) from parent-offspring trios have reported multiple putatively causal genes. However, a joint analysis method designed to integrate DNMs from multiple studies has yet to be implemented.

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Background: Polygenic risk scores (PRS) for coronary artery disease (CAD) identify high-risk individuals more likely to benefit from primary prevention statin therapy. Whether polygenic CAD risk is captured by conventional paradigms for assessing clinical cardiovascular risk remains unclear.

Objectives: This study sought to intersect polygenic risk with guideline-based recommendations and management patterns for CAD primary prevention.

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To reveal post-traumatic stress disorder (PTSD) genetic risk influences on tissue-specific gene expression, we use brain and non-brain transcriptomic imputation. We impute genetically regulated gene expression (GReX) in 29,539 PTSD cases and 166,145 controls from 70 ancestry-specific cohorts and identify 18 significant GReX-PTSD associations corresponding to specific tissue-gene pairs. The results suggest substantial genetic heterogeneity based on ancestry, cohort type (military versus civilian), and sex.

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Background & Aims: Collagenous colitis (CC) is an inflammatory bowel disorder with unknown etiopathogenesis involving HLA-related immune-mediated responses and environmental and genetic risk factors. We carried out an array-based genetic association study in a cohort of patients with CC and investigated the common genetic basis between CC and Crohn's disease (CD), ulcerative colitis (UC), and celiac disease.

Methods: DNA from 804 CC formalin-fixed, paraffin-embedded tissue samples was genotyped with Illumina Immunochip.

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Article Synopsis
  • Hereditary transthyretin amyloid cardiomyopathy (hATTR-CM) due to the TTR V122I variant causes heart failure, particularly in older individuals of African ancestry, but its clinical impacts in other populations remain unclear.
  • The objective of the study was to explore the link between the TTR V122I variant and heart failure, while also examining how often carriers of the variant are diagnosed with hATTR-CM.
  • The study involved a large analysis of individuals enrolled in biobanks, revealing that 3.1% of those studied were TTR V122I carriers and that 30% had heart failure, highlighting a significant issue regarding diagnosis rates among these carriers.
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  • The study investigates how common genetic variants related to schizophrenia (SZ) interact to influence complex genetic disorders using human induced pluripotent stem cells (iPSCs).
  • Researchers utilized CRISPR technology to focus on specific SZ-related genes and found that these genes impact neuronal function and gene expression differently based on cell type.
  • The findings suggest that there is a significant interaction between common and rare genetic variants in contributing to the risk of psychiatric diseases, potentially applicable to other complex genetic disorders as well.
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RNA editing critically regulates neurodevelopment and normal neuronal function. The global landscape of RNA editing was surveyed across 364 schizophrenia cases and 383 control postmortem brain samples from the CommonMind Consortium, comprising two regions: dorsolateral prefrontal cortex and anterior cingulate cortex. In schizophrenia, RNA editing sites in genes encoding AMPA-type glutamate receptors and postsynaptic density proteins were less edited, whereas those encoding translation initiation machinery were edited more.

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In the HTML version of the article originally published, the author group 'The Schizophrenia Working Group of the Psychiatric Genomics Consortium' was displayed incorrectly. The error has been corrected in the HTML version of the article.

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Article Synopsis
  • * The analysis discovered 30 significant genetic loci linked to bipolar disorder, including 20 that hadn't been previously identified, which involve genes related to ion channels and neurotransmitter systems.
  • * The study also showed that Bipolar I disorder has a genetic connection to schizophrenia, particularly linked to psychosis, while Bipolar II disorder is more closely related to major depressive disorder, shedding light on potential biological mechanisms and clinical implications.
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Transcriptomic imputation approaches combine eQTL reference panels with large-scale genotype data in order to test associations between disease and gene expression. These genic associations could elucidate signals in complex genome-wide association study (GWAS) loci and may disentangle the role of different tissues in disease development. We used the largest eQTL reference panel for the dorso-lateral prefrontal cortex (DLPFC) to create a set of gene expression predictors and demonstrate their utility.

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Causal genes and variants within genome-wide association study (GWAS) loci can be identified by integrating GWAS statistics with expression quantitative trait loci (eQTL) and determining which variants underlie both GWAS and eQTL signals. Most analyses, however, consider only the marginal eQTL signal, rather than dissect this signal into multiple conditionally independent signals for each gene. Here we show that analyzing conditional eQTL signatures, which could be important under specific cellular or temporal contexts, leads to improved fine mapping of GWAS associations.

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Background: Integrating rare variation from trio family and case-control studies has successfully implicated specific genes contributing to risk of neurodevelopmental disorders (NDDs) including autism spectrum disorders (ASD), intellectual disability (ID), developmental disorders (DDs), and epilepsy (EPI). For schizophrenia (SCZ), however, while sets of genes have been implicated through the study of rare variation, only two risk genes have been identified.

Methods: We used hierarchical Bayesian modeling of rare-variant genetic architecture to estimate mean effect sizes and risk-gene proportions, analyzing the largest available collection of whole exome sequence data for SCZ (1,077 trios, 6,699 cases, and 13,028 controls), and data for four NDDs (ASD, ID, DD, and EPI; total 10,792 trios, and 4,058 cases and controls).

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Objective: There is no evidence for a genetic association between organic anion transporters 1-3 (SLC22A6, SLC22A7, and SLC22A8) and multidrug resistance protein 4 (MRP4; encoded by ABCC4) with the levels of serum urate or gout. The Māori and Pacific (Polynesian) population of New Zealand has the highest prevalence of gout worldwide. The aim of this study was to determine whether any Polynesian population-specific genetic variants in SLC22A6-8 and ABCC4 are associated with gout.

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Large genome-wide association studies (GWAS) have identified many genetic loci associated with risk for myocardial infarction (MI) and coronary artery disease (CAD). Concurrently, efforts such as the National Institutes of Health (NIH) Roadmap Epigenomics Project and the Encyclopedia of DNA Elements (ENCODE) Consortium have provided unprecedented data on functional elements of the human genome. In the present study, we systematically investigate the biological link between genetic variants associated with this complex disease and their impacts on gene function.

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