Daily Cardiology Research Analysis
Three landmark human genetics studies reshape cardiovascular science: rare coding and structural variants that cause atrial fibrillation (AF) are identified and functionally validated; a meta-analysis doubles known AF risk loci and delivers a stronger polygenic risk score; and CXCL12 is revealed as a developmental driver of coronary artery dominance with supporting mouse and human data.
Summary
Three landmark human genetics studies reshape cardiovascular science: rare coding and structural variants that cause atrial fibrillation (AF) are identified and functionally validated; a meta-analysis doubles known AF risk loci and delivers a stronger polygenic risk score; and CXCL12 is revealed as a developmental driver of coronary artery dominance with supporting mouse and human data.
Research Themes
- Human genetics and multi-omics redefine atrial fibrillation risk architecture
- Developmental signaling (CXCL12) shapes coronary artery anatomy
- Translational genomics enabling precision cardiovascular risk prediction
Selected Articles
1. Sequencing in over 50,000 cases identifies coding and structural variation underlying atrial fibrillation risk.
This meta-analysis of genome/exome sequencing across 52,416 AF cases and 277,762 controls identifies new rare coding genes (e.g., MYBPC3, LMNA, PKP2, FAM189A2, KDM5B) and structural variants (CTNNA3 deletions, GATA4 duplications) associated with AF. Findings were broadly replicated, and CRISPR knockout of KDM5B in atrial cardiomyocytes shortened action potential duration, linking rare variants to atrial electrophysiology.
Impact: Defines the rare variant architecture of AF with functional validation, strengthening causal inference and linking AF to cardiomyopathy genes.
Clinical Implications: Genetic testing panels for AF may incorporate these rare coding and structural variants; mechanistic insights (e.g., KDM5B) could inform novel antiarrhythmic targets and risk stratification beyond common variant PRS.
Key Findings
- Rare coding variants in MYBPC3, LMNA, PKP2, FAM189A2, and KDM5B are associated with AF by burden testing.
- Rare structural variants—CTNNA3 deletions and GATA4 duplications—confer AF risk.
- CRISPR KDM5B knockout in atrial cardiomyocytes shortens action potential duration and disrupts atrial homeostasis gene programs.
- Associations and effects replicate across independent cohorts (MyCode, deCODE, UK Biobank).
Methodological Strengths
- Very large sequencing meta-analysis with replication across multiple independent cohorts
- Functional validation via CRISPR perturbation in human atrial cardiomyocytes
Limitations
- Case-control genetic design limits direct clinical phenotyping and environmental interactions
- Translational path from variant discovery to clinical testing and therapy requires further study across ancestries
Future Directions: Integrate rare variants into clinical AF genetic panels; test gene-specific mechanisms (e.g., KDM5B pathways) for therapeutic targeting; assess penetrance and modifiers across ancestries.
Atrial fibrillation (AF) is a prevalent and morbid abnormality of the heart rhythm with a strong genetic component. Here, we meta-analyzed genome and exome sequencing data from 36 studies that included 52,416 AF cases and 277,762 controls. In burden tests of rare coding variation, we identified novel associations between AF and the genes MYBPC3, LMNA, PKP2, FAM189A2 and KDM5B. We further identified associations between AF and rare structural variants owing to deletions in CTNNA3 and duplications of GATA4. We broadly replicated our findings in independent samples from MyCode, deCODE and UK Biobank. Finally, we found that CRISPR knockout of KDM5B in stem-cell-derived atrial cardiomyocytes led to a shortening of the action potential duration and widespread transcriptomic dysregulation of genes relevant to atrial homeostasis and conduction. Our results highlight the contribution of rare coding and structural variants to AF, including genetic links between AF and cardiomyopathies, and expand our understanding of the rare variant architecture for this common arrhythmia.
2. CXCL12 drives natural variation in coronary artery anatomy across diverse populations.
A cross-ancestry GWAS of coronary dominance in >60,000 angiograms identified 10 loci, with the strongest signal near CXCL12. CXCL12 is expressed in human fetal hearts when dominance is set, and reducing Cxcl12 in mice shifts dominance and septal artery trajectories, establishing a developmental mechanism for coronary anatomy.
Impact: Links a specific chemokine pathway to human coronary patterning with convergent human genetics and mouse perturbation, opening a mechanistic basis for anatomical variability relevant to revascularization strategies.
Clinical Implications: Understanding genetic control of coronary dominance may inform pre-procedural planning, risk stratification for ischemia, and future concepts of "medical revascularization" by modulating developmental pathways.
Key Findings
- GWAS of >60,000 angiograms identified 10 loci influencing coronary dominance with moderate heritability.
- Strongest association localized near CXCL12 across European- and African-ancestry cohorts, implicating CXCL12 expression.
- CXCL12 is expressed in human fetal hearts at the time dominance is established.
- Cxcl12 reduction in mice alters coronary dominance and redirects septal artery development.
Methodological Strengths
- Large cross-ancestry GWAS with angiographic phenotyping of coronary dominance
- Orthogonal validation with human fetal expression and mouse genetic perturbation
Limitations
- Cohort drawn from US veterans may limit generalizability (e.g., sex and age distribution)
- Translational applications require further study to modulate developmental pathways safely
Future Directions: Map cellular targets and timing for CXCL12-mediated coronary patterning, evaluate genetic predictors of procedural outcomes, and explore pharmacologic modulation in preclinical models.
Coronary arteries have a specific branching pattern crucial for oxygenating heart muscle. Among humans, there is natural variation in coronary anatomy with respect to perfusion of the inferior/posterior left heart, which can branch from either the right arterial tree, the left, or both-a phenotype known as coronary dominance. Using angiographic data for >60,000 US veterans of diverse ancestry, we conducted a genome-wide association study of coronary dominance, revealing moderate heritability and identifying ten significant loci. The strongest association occurred near CXCL12 in both European- and African-ancestry cohorts, with downstream analyses implicating effects on CXCL12 expression. We show that CXCL12 is expressed in human fetal hearts at the time dominance is established. Reducing Cxcl12 in mice altered coronary dominance and caused septal arteries to develop away from Cxcl12 expression domains. These findings indicate that CXCL12 patterns human coronary arteries, paving the way for "medical revascularization" through targeting developmental pathways.
3. Meta-analysis of genome-wide associations and polygenic risk prediction for atrial fibrillation in more than 180,000 cases.
By meta-analyzing AF GWAS (>180,000 cases), the study identifies over 350 loci and functionally annotates 139 through chromatin assays in atrial cardiomyocytes. An updated AF polygenic risk score outperforms both the CHARGE-AF clinical score and prior PRS, strengthening genomic risk prediction.
Impact: Doubles known AF loci and delivers a higher-performing PRS with mechanistic chromatin support in atrial cardiomyocytes, directly enabling precision risk stratification.
Clinical Implications: Improved AF polygenic risk scoring may augment clinical risk tools (e.g., CHA2DS2-VASc context) and identify high-risk individuals for monitoring, prevention, or early rhythm-control strategies.
Key Findings
- Meta-analysis identifies >350 AF-associated loci, doubling known risk architecture.
- At 139 loci, candidate genes tied to muscle contractility, cardiac development, and cell-cell communication are prioritized.
- Chromatin accessibility (ATAC-seq) and H3K4me3 support sentinel variant activity in atrial cardiomyocytes.
- An updated AF PRS outperforms CHARGE-AF and prior PRS in risk prediction.
Methodological Strengths
- Extremely large GWAS meta-analysis with functional epigenomic annotation in relevant human cells
- Direct comparative evaluation of PRS performance against clinical and prior genomic scores
Limitations
- Summary-level meta-analysis limits fine-grained phenotype resolution and gene-environment interaction assessment
- PRS transferability across diverse ancestries requires further validation and optimization
Future Directions: Implement PRS in prospective cohorts and health systems, test ancestry-specific/transfer learning approaches, and integrate PRS with rare variants for composite AF genetic risk tools.
Atrial fibrillation (AF) is the most common heart rhythm abnormality and is a leading cause of heart failure and stroke. This large-scale meta-analysis of genome-wide association studies increased the power to detect single-nucleotide variant associations and found more than 350 AF-associated genetic loci. We identified candidate genes related to muscle contractility, cardiac muscle development and cell-cell communication at 139 loci. Furthermore, we assayed chromatin accessibility using assay for transposase-accessible chromatin with sequencing and histone H3 lysine 4 trimethylation in stem cell-derived atrial cardiomyocytes. We observed a marked increase in chromatin accessibility for our sentinel variants and prioritized genes in atrial cardiomyocytes. Finally, a polygenic risk score (PRS) based on our updated effect estimates improved AF risk prediction compared to the CHARGE-AF clinical risk score and a previously reported PRS for AF. The doubling of known risk loci will facilitate a greater understanding of the pathways underlying AF.