| 1. |
- Roselli, Carolina, et al.
(author)
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Multi-ethnic genome-wide association study for atrial fibrillation
- 2018
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:9, s. 1225-1233
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Journal article (peer-reviewed)abstract
- Atrial fibrillation (AF) affects more than 33 million individuals worldwide(1) and has a complex heritability(2). We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF.
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| 2. |
- Aragam, Krishna G., et al.
(author)
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Phenotypic Refinement of Heart Failure in a National Biobank Facilitates Genetic Discovery
- 2019
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In: Circulation. - 0009-7322. ; 139:4, s. 489-501
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Journal article (peer-reviewed)abstract
- Heart failure (HF) is a morbid and heritable disorder for which the biological mechanisms are incompletely understood. We therefore examined genetic associations with HF in a large national biobank, and assessed whether refined phenotypic classification would facilitate genetic discovery. Methods: We defined all-cause HF among 488 010 participants from the UK Biobank and performed a genome-wide association analysis. We refined the HF phenotype by classifying individuals with left ventricular dysfunction and without coronary artery disease as having nonischemic cardiomyopathy (NICM), and repeated a genetic association analysis. We then pursued replication of lead HF and NICM variants in independent cohorts, and performed adjusted association analyses to assess whether identified genetic associations were mediated through clinical HF risk factors. In addition, we tested rare, loss-of-function mutations in 24 known dilated cardiomyopathy genes for association with HF and NICM. Finally, we examined associations between lead variants and left ventricular structure and function among individuals without HF using cardiac magnetic resonance imaging (n=4158) and echocardiographic data (n=30 201). Results: We identified 7382 participants with all-cause HF in the UK Biobank. Genome-wide association analysis of all-cause HF identified several suggestive loci (P<1×10 -6 ), the majority linked to upstream HF risk factors, ie, coronary artery disease (CDKN2B-AS1 and MAP3K7CL) and atrial fibrillation (PITX2). Refining the HF phenotype yielded a subset of 2038 NICM cases. In contrast to all-cause HF, genetic analysis of NICM revealed suggestive loci that have been implicated in dilated cardiomyopathy (BAG3, CLCNKA-ZBTB17). Dilated cardiomyopathy signals arising from our NICM analysis replicated in independent cohorts, persisted after HF risk factor adjustment, and were associated with indices of left ventricular dysfunction in individuals without clinical HF. In addition, analyses of loss-of-function variants implicated BAG3 as a disease susceptibility gene for NICM (loss-of-function variant carrier frequency=0.01%; odds ratio,12.03; P=3.62×10 -5 ). Conclusions: We found several distinct genetic mechanisms of all-cause HF in a national biobank that reflect well-known HF risk factors. Phenotypic refinement to a NICM subtype appeared to facilitate the discovery of genetic signals that act independently of clinical HF risk facto rs and that are associated with subclinical left ventricular dysfunction.
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| 3. |
- Berntsson, John, et al.
(author)
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Risk of Stroke in Patients With Atrial Fibrillation Is Associated With Stroke in Siblings : A Nationwide Study
- 2020
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In: Journal of the American Heart Association. - 2047-9980. ; 9:3, s. 014132-014132
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Journal article (peer-reviewed)abstract
- Background: It remains unclear whether heritable factors can contribute to risk stratification for ischemic stroke in patients with atrial fibrillation (AF). We examined whether having a sibling with ischemic stroke was associated with increased risk of ischemic stroke and mortality in patients with AF. Methods and Results: In this nationwide study of the Swedish population, patients with AF and their siblings were identified from the Swedish patient registers and the Swedish MGR (Multi-Generation Register). Ischemic stroke events were retrieved from the Swedish patient registers and CDR (Cause of Death Register). Risk of ischemic stroke was compared between patients with AF with and without a sibling affected by ischemic stroke, AF, or both ischemic stroke and AF. The total study population comprised 113 988 subjects (mean age, 60±12 years) diagnosed with AF between 1989 and 2012. In total, 11 709 of them were diagnosed with a first ischemic stroke and 20 097 died during a mean follow-up time of 5.5 years for ischemic stroke and 5.9 years for mortality. After adjustment for covariates having a sibling with ischemic stroke, or both ischemic stroke and AF, was associated with increased risk of ischemic stroke (hazard ratio, 1.31; 95% CI, 1.23-1.40 or hazard ratio, 1.36; 95% CI, 1.24-1.49, respectively). Furthermore, ischemic stroke in a sibling was associated with all-cause mortality (hazard ratio, 1.09; 95% CI, 1.05-1.14). In contrast, the risk of stroke was only marginally increased for patients with AF with a spouse affected by ischemic stroke. Conclusions: Having a sibling affected by ischemic stroke confers an increased risk of ischemic stroke and death independently of traditional risk factors in patients with AF.
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| 4. |
- Weng, Lu Chen, et al.
(author)
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Heritability of Atrial Fibrillation
- 2017
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In: Circulation: Cardiovascular Genetics. - 1942-325X. ; 10:6
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Journal article (peer-reviewed)abstract
- Background - Previous reports have implicated multiple genetic loci associated with AF, but the contributions of genome-wide variation to AF susceptibility have not been quantified. Methods and Results - We assessed the contribution of genome-wide single-nucleotide polymorphism variation to AF risk (single-nucleotide polymorphism heritability, h2 g) using data from 120 286 unrelated individuals of European ancestry (2987 with AF) in the population-based UK Biobank. We ascertained AF based on self-report, medical record billing codes, procedure codes, and death records. We estimated h2 g using a variance components method with variants having a minor allele frequency ≥1%. We evaluated h2 g in age, sex, and genomic strata of interest. The h2 g for AF was 22.1% (95% confidence interval, 15.6%-28.5%) and was similar for early- versus older-onset AF (≤65 versus >65 years of age), as well as for men and women. The proportion of AF variance explained by genetic variation was mainly accounted for by common (minor allele frequency, ≥5%) variants (20.4%; 95% confidence interval, 15.1%-25.6%). Only 6.4% (95% confidence interval, 5.1%-7.7%) of AF variance was attributed to variation within known AF susceptibility, cardiac arrhythmia, and cardiomyopathy gene regions. Conclusions - Genetic variation contributes substantially to AF risk. The risk for AF conferred by genomic variation is similar to that observed for several other cardiovascular diseases. Established AF loci only explain a moderate proportion of disease risk, suggesting that further genetic discovery, with an emphasis on common variation, is warranted to understand the causal genetic basis of AF.
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