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Project description:Genome-wide association studies (GWAS) have linked hundreds of loci to cardiac diseases. However, in most loci the causal variants and their target genes remain unknown. We developed a combined experimental and analytical approach that integrates single cell epigenomics with GWAS to prioritize risk variants and genes. We profiled accessible chromatin in single cells obtained from human hearts and leveraged the data to study genetics of Atrial Fibrillation (AF), the most common cardiac arrhythmia. Enrichment analysis of AF risk variants using cell-type-resolved open chromatin regions (OCRs) implicated cardiomyocytes as the main mediator of AF risk. We then performed statistical fine-mapping, leveraging the information in OCRs, and identified putative causal variants in 122 AF-associated loci. Taking advantage of the fine-mapping results, our novel statistical procedure for gene discovery prioritized 45 high-confidence risk genes, highlighting transcription factors and signal transduction pathways important for heart development. We further leveraged our single-cell data to study genetics of gene expression. An unexpected finding from earlier studies is that expression QTLs (eQTLs) are often shared across tissues even though most regulatory elements are cell-type specific. We found that this sharing is largely driven by the limited power of eQTL studies using bulk tissues to detect cell-type-specific regulatory variants. This finding points to an important limitation of using eQTLs to interpret GWAS of complex traits. In summary, our analysis provides a comprehensive map of AF risk variants and genes, and a general framework to integrate single-cell genomics with genetic studies of complex traits.
2023-02-12 | GSE224996 | GEO
Project description:Genome-wide association studies (GWAS) have linked hundreds of loci to cardiac diseases. However, in most loci the causal variants and their target genes remain unknown. We developed a combined experimental and analytical approach that integrates single cell epigenomics with GWAS to prioritize risk variants and genes. We profiled accessible chromatin in single cells obtained from human hearts and leveraged the data to study genetics of Atrial Fibrillation (AF), the most common cardiac arrhythmia. Enrichment analysis of AF risk variants using cell-type-resolved open chromatin regions (OCRs) implicated cardiomyocytes as the main mediator of AF risk. We then performed statistical fine-mapping, leveraging the information in OCRs, and identified putative causal variants in 122 AF-associated loci. Taking advantage of the fine-mapping results, our novel statistical procedure for gene discovery prioritized 45 high-confidence risk genes, highlighting transcription factors and signal transduction pathways important for heart development. We further leveraged our single-cell data to study genetics of gene expression. An unexpected finding from earlier studies is that expression QTLs (eQTLs) are often shared across tissues even though most regulatory elements are cell-type specific. We found that this sharing is largely driven by the limited power of eQTL studies using bulk tissues to detect cell-type-specific regulatory variants. This finding points to an important limitation of using eQTLs to interpret GWAS of complex traits. In summary, our analysis provides a comprehensive map of AF risk variants and genes, and a general framework to integrate single-cell genomics with genetic studies of complex traits.
2023-02-12 | GSE224995 | GEO
Project description:Atrial fibrillation (AF) is a common clinical arrhythmia that appears to be highly heritable, despite representing a complex interplay of several disease processes that generally do not manifest until later in life. In this manuscript, we will review the genetic basis of this complex trait established through studies of familial AF, linkage and candidate gene studies of common AF, genome wide association studies (GWAS) of common AF, and transcriptomic studies of AF. Since AF is associated with a five-fold increase in the risk of stroke, we also review the intersection of common genetic factors associated with both of these conditions. Similarly, we highlight the intersection of common genetic markers associated with some risk factors for AF, such as hypertension and obesity, and AF. Lastly, we describe a paradigm where genetic factors predispose to the risk of AF, but which may require additional stress and trigger factors in older age to allow for the clinical manifestation of AF.
| S-EPMC5386395 | biostudies-literature
Project description:Expression analysis of whole tissue and cardiomyocytes of fetal and adult atrial free wall
2019-10-29 | GSE127856 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2020-07-10 | GSE148507 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2024-05-02 | GSE198788 | GEO
Project description:Disease-associated genetic variants that lie in non-coding regions found by genome-wide association studies are thought to alter the functionality of transcription regulatory elements and target gene expression. To uncover causal genetic variants, variant regulatory elements and their target genes, here we cross-reference human transcriptomic, epigenomic and chromatin conformation datasets. Of 104 genetic variant regions associated with atrial fibrillation candidate target genes are prioritized. We optimize EMERGE enhancer prediction and use accessible chromatin profiles of human atrial cardiomyocytes to more accurately predict cardiac regulatory elements and identify hundreds of sub-threshold variants that co-localize with regulatory elements. Removal of mouse homologues of atrial fibrillation-associated regions in vivo uncovers a distal regulatory region involved in Gja1 (Cx43) expression. Our analyses provide a shortlist of genes likely affected by atrial fibrillation-associated variants and provide variant regulatory elements in each region that link genetic variation and target gene regulation, helping to focus future investigations.
| S-EPMC6802215 | biostudies-literature
Project description:Most sequence variants identified hitherto in genome-wide association studies (GWAS) of atrial fibrillation are common, non-coding variants associated with risk through unknown mechanisms. We performed a meta-analysis of GWAS of atrial fibrillation among 29,502 cases and 767,760 controls from Iceland and the UK Biobank with follow-up in samples from Norway and the US, focusing on low-frequency coding and splice variants aiming to identify causal genes. We observe associations with one missense (OR?=?1.20) and one splice-donor variant (OR?=?1.50) in RPL3L, the first ribosomal gene implicated in atrial fibrillation to our knowledge. Analysis of 167 RNA samples from the right atrium reveals that the splice-donor variant in RPL3L results in exon skipping. We also observe an association with a missense variant in MYZAP (OR?=?1.38), encoding a component of the intercalated discs of cardiomyocytes. Both discoveries emphasize the close relationship between the mechanical and electrical function of the heart.
| S-EPMC6123807 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2024-09-24 | GSE255992 | GEO
Project description:BackgroundGenome-wide association studies have shown that the common single nucleotide polymorphism rs6800541 located in SCN10A, encoding the voltage-gated Nav1.8 sodium channel, is associated with PR-interval prolongation and atrial fibrillation (AF). Single nucleotide polymorphism rs6800541 is in high linkage disequilibrium with the nonsynonymous variant in SCN10A, rs6795970 (V1073A, r(2)=0.933). We therefore sought to determine whether common and rare SCN10A variants are associated with early onset AF.Methods and resultsSCN10A was sequenced in 225 AF patients in whom there was no evidence of other cardiovascular disease or dysfunction (lone AF). In an association study of the rs6795970 single nucleotide polymorphism variant, we included 515 AF patients and 2 control cohorts of 730 individuals free of AF and 6161 randomly sampled individuals. Functional characterization of SCN10A variants was performed by whole-cell patch-clamping. In the lone AF cohort, 9 rare missense variants and 1 splice site donor variant were detected. Interestingly, AF patients were found to have higher G allele frequency of rs6795970, which encodes the alanine variant at position 1073 (described from here on as A1073, odds ratio =1.35 [1.16-1.54]; P=2.3×10(-5)). Both of the common variants, A1073 and P1092, induced a gain-of-channel function, whereas the rare missense variants, V94G and R1588Q, resulted in a loss-of-channel function.ConclusionsThe common variant A1073 is associated with increased susceptibility to AF. Both rare and common variants have effect on the function of the channel, indicating that these variants influence susceptibility to AF. Hence, our study suggests that SCN10A variations are involved in the genesis of AF.
| S-EPMC4392342 | biostudies-literature