Circulation: Genomic and Precision Medicine

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of cardioembolic stroke. Although polygenic risk scores (PRS) are well characterized to quantify inherited susceptibility for AF, they provide limited insight into the pathways and tissues underlying genetic risk, which are critical to uncover for individual risk prediction. In this study, we develop a pathway-level multi-omics representation learning framework that converts individual genetic profiles into interpretable biological features by integrating GWAS-derived pathway burden scores with tissue-specific transcriptomic pathway signals. We constructed machine learning models to assess population-level AF risk prediction performance across genomic and transcriptomic tissue contexts; the pathway-based global attention models substantially improved risk prediction performance over PRS and other baselines (AUROC improved from 0.601 to 0.738). Transformer and graph neural network frameworks then assessed individual-level pathway interpretability, revealing heterogeneous contributions from electrical signaling, cardiac development, and DNA repair pathways to AF risk. This added interpretability highlights the potential of this pathway approach to enable more mechanistically informed risk stratification than static PRS by capturing underlying heterogeneity. To independently assess whether prioritized pathways reflected cardiac regulatory biology, we compared pathway rankings with transcriptional effects predicted by the AlphaGenome foundation model. Variants in highly ranked pathways showed significantly greater predicted effects on expression in atrial and ventricular tissues (FDR = 0.032) relative to controls, providing orthogonal evidence that the model identifies biologically relevant mechanisms. Overall, this work reframes polygenic risk from a single measure of susceptibility to tissue-informed pathway mechanisms, providing a framework for interpretable genomic stratification in complex diseases.

Background. Cuproptosis, a copper-dependent form of regulated cell death, has been repeatedly reported to be transcriptionally activated in atherosclerotic plaque, and cuproptosis- and copper-transport genes have been nominated as candidate biomarkers and therapeutic targets on the basis of descriptive expression studies. Whether genetically determined expression of these genes is causally related to atherosclerotic cardiovascular disease has not been tested. Methods. We first confirmed, across two independent carotid plaque transcriptomic cohorts (GSE43292 and GSE28829), that a panel of copper-metabolism and cuproptosis genes is concordantly dysregulated in plaque and that the copper importers track the degree of inflammatory-cell infiltration. We then performed two-sample cis-Mendelian randomization (MR) and Bayesian colocalization to test the causal effect of the genetically predicted expression of 11 cuproptosis/copper genes on coronary artery disease (CAD). Instruments were cis-eQTLs from whole-blood (eQTLGen, n = 31,684) and tibial artery (GTEx v8, n = 584); the outcome was CAD (CARDIoGRAMplusC4D/Aragam 2022; 181,522 cases, 1,165,690 participants, European ancestry). Large-artery atherosclerotic stroke (GIGASTROKE) was examined as a secondary outcome. LPL served as a positive control. The positive control was intended to validate the direction and harmonization of the MR pipeline, not to demonstrate that single-causal-variant colocalization must succeed at a known multi-signal locus such as LPL. Results. In plaque, copper-import genes (SLC31A2, SLC31A1) were upregulated and correlated strongly with myeloid/inflammatory infiltration (SLC31A2 vs. M1-macrophage r = +0.87), whereas the exporter ATP7B correlated inversely (r = -0.73). The positive control LPL showed the expected robust protective effect on CAD (IVW OR 0.90 per SD higher expression, 95% CI 0.87-0.93, P = 4.1 x 10-12), validating the pipeline. None of the 11 cuproptosis/copper genes showed colocalization-supported causal evidence for CAD. Two genes reached nominal MR significance in single-instrument analyses (MTF1 OR 1.16, P = 2.7 x 10-3, DLAT OR 1.41, P = 2.2 x 10-3,) but were not supported by colocalization (MTF1 PP.H4 = 4 x 10-6 with PP.H3 = 0.9998; DLAT PP.H4 = 0.29), indicating linkage-disequilibrium confounding rather than causality. For well-instrumented genes (e.g. ATP7B, SLC31A2, FDX1), estimates were null and precise enough to exclude odds ratios larger than {approx}1.05 per SD. Conclusions. Common cis-regulatory variation determining the baseline expression of cuproptosis/copper-transport genes in available eQTL tissues did not support a detectable causal effect on CAD risk. This does not exclude locally acquired plaque cuproptosis; rather, the reported upregulation of these genes in plaque is most consistent with a consequence or marker of established disease rather than a germline-encoded causal driver, and cautions against target nomination based on descriptive transcriptomics alone. Keywords: cuproptosis; atherosclerosis; coronary artery disease; Mendelian randomization; colocalization

Arrhythmogenic cardiomyopathy (ACM) is an inherited disease characterized by fibrofatty remodeling and sudden cardiac death linked to desmosomal dysfunction. Yet, 40% of cases remain genetically unexplained, and non-desmosomal mutations offer insight into ACM pathophysiology. Myoferlin (MYOF), a calcium (Ca2+)-binding protein in cardiomyocytes, is linked to cardiomyopathy, but its mechanism remains unknown. Whole-exome sequencing identified a heterozygous MYOF missense variant (p.G1654S) in an ACM family; we subsequently found three unrelated p.G1654S cases. We hypothesized that MYOF deficiency promotes Ca2+ handling deficits and arrhythmogenesis in ACM. In patient iPSC-derived cardiomyocytes, MYOF p.G1654S protein dimerized with wild-type protein and underwent accelerated lysosomal degradation, showed disrupted Ca2+ handling, and displayed increased arrhythmia burden, all rescued by genomic correction. MYOF interacted with CaV1.2, and verapamil pharmacologically rescued arrhythmias. Heterozygous Myof knockout mice showed systolic dysfunction and fibrosis. These findings establish MYOF as a causative ACM gene and therapeutic target that mediates arrhythmogenesis by disrupting MYOF-CaV1.2.

Aims: Arrhythmogenic cardiomyopathy (ACM) is a genetic disease defined by arrhythmias and myocardial fibrosis with impaired cardiac function and increased risk of sudden cardiac death. Pathogenic variants are mostly identified in desmosomal genes such as desmoglein-2 (DSG2). We identified a novel disease phenotype in patients homozygous for the DSG2 variant c.523+2T>C (splice site of exon 5/intron 5), characterized by cardioembolic events in addition to classical ACM features. Here, we evaluate this new thromboembolic phenotype by comparing the clinical data to specific murine disease models. Methods and Results: We describe three unrelated patients presenting with an embolic event and/or left ventricular thrombus. Clinical evaluation revealed a shared right ventricular ACM phenotype characterized by arrhythmias, impaired function, and fibrotic remodeling. In addition, patients exhibited localized fibrotic changes of the left ventricular apex with formation of an aneurysm and predisposition to thrombus formation. Genetic analysis identified the DSG2 variant c.523+2T>C as a founder variant from the "Bernese Oberland". To elucidate the variant's functional impact, a mouse model deficient for Dsg2 exon 5 (Dsg2{Delta}ex5) was established and compared to a model carrying the adhesion-deficient Dsg2-W2A variant. Echocardiography, ECG, and histology in Dsg2{Delta}ex5 mice revealed similar disease patterns to patients and a loss of DSG2 expression. Importantly, these animals exhibited left apical fibrosis with aneurysm formation and left ventricular thrombus formation. In contrast, the Dsg2-W2A model presented with a biventricular ACM-phenotype but without left ventricular thrombi. Conclusions: We identified a novel ACM phenotype in patients homozygous for the DSG2 founder variant c.523+2T>C characterized by left ventricular apical fibrosis. Dsg2{Delta}ex5 mice recapitulate the patients' phenotype suggesting a causative link between left ventricular aneurysm due to DSG2 deficiency and thrombus formation with subsequent embolism. This highlights a novel pathological feature of ACM and the need for variant and phenotype-specific therapy.

Background: Cascade screening increasingly identifies carriers of pathogenic or likely pathogenic sarcomere variants at risk for hypertrophic cardiomyopathy (HCM) in whom penetrance is incomplete, and surveillance relies on resource-intensive serial imaging. We evaluated whether a validated artificial intelligence-enhanced electrocardiography (AI-ECG) model identifies the HCM phenotype at first clinical assessment, predicts development of HCM during follow-up, and complements polygenic risk. Methods: We assembled 1,095 genotype-positive (G+) individuals with pathogenic or likely pathogenic sarcomere variants from Yale-New Haven Hospital (n=119), Erasmus MC (n=858), and Motol University Hospital (n=118). At baseline (first clinical assessment), individuals were classified as phenotype-positive (P+) or phenotype-negative (P-). A previously validated AI-ECG model applied to 12-lead ECG images generated an HCM score. The primary outcome was detection of phenotypic positivity at baseline; secondary analyses included manifest HCM (at baseline or during follow-up) and identifying risk of developing future HCM among G+/P- individuals. In 57,007 UK Biobank participants, we assessed whether AI-ECG adds to an established polygenic risk score (PRS). Results: Among 1,095 G+ individuals (median age 46 years [IQR 34- 56]; 52.1% female), 808 (73.8%) were P+ at baseline, 56 (5.1%) developed HCM during follow-up, and 231 (21.1%) remained P-. AI-ECG achieved an AUROC of 0.91 (95% CI 0.89-0.93) for P+ at baseline and 0.92 (95% CI 0.90-0.94) for manifest HCM. At a threshold of 0.15, sensitivity was 0.78, specificity 0.89, PPV 0.95, and NPV 0.59. Among G+/P- individuals, higher AI-ECG scores predicted development of HCM (HR 1.55 per 1-SD; 95% CI 1.28- 1.88; p< 0.001; adjusted HR 1.38; 95% CI 1.11- 1.71; p=0.004). In the UK Biobank, individuals with both high AI-ECG and high PRS had 60-fold higher odds of HCM (adjusted OR 60.2; 95% CI 26.5- 137.2), versus 15.0 for high AI-ECG alone and 4.1 for high PRS alone. Conclusions: AI-ECG detects the HCM phenotype at baseline in sarcomere variant carriers, predicts development of HCM in G+/P- individuals, and complements PRS in the general population, supporting AI-ECG as a scalable tool to detect HCM and guide surveillance in individuals with monogenic or polygenic susceptibility.

Background: Metabolic perturbations associated with cardiovascular disease (CVD) risk factors prior to clinical disease manifestation may inform novel preventative measures. Here we characterize metabolome-wide associations with various cardiometabolic risk factors in an asymptomatic population to develop a mechanistic metabolic framework of preemergent metabolic shifts. Methods: Plasma was collected from a clinically healthy cross-sectional cohort (n = 361; Clinical Trials.gov ID: NCT02367287). Cohort mass spectrometry-based metabolomics (biocrates MxP(R) Quant 500 kits) were complemented with expanded lipidomic coverage for a sex/age-matched subset with LDLc difference > 60 mg/dL (n = 38). LDLc-focused partial least square regressions and discriminate analyses were performed, after false discovery rate corrections. Results: As LDLc levels increased, plasma sphingolipids and cholesteryl esters, and transulfuration products were higher, while ether-linked phosphatidylcholines serine, glycine, alanine, methionine were lower. The subset analysis further highlighted elevations in triglycerides and deoxyceramides with elevated LDLc. When adjusted for alanine concentrations, deoxyceramide concentrations increased as serine declined (p = 0.0012), and the deoxyceramide:ceramide ratios were higher in the high LDLc group (p = 0.039). Lower serine levels were also accompanied by parallel changes in glycine (p= 0.0004), and anti-parallel changes in transsulfuration pathway metabolites particularly when adjusted for ceramide levels. Notably, the alanine:serine ratio was more strongly associated with fasting triglycerides (r = 0.38; p <0.0001) than LDLc. Conclusions: Serine depletion by increased demands of sphingolipid, and possibly transsulfuration pathway, metabolism is associated with elevations in cytotoxic deoxyceramides and reductions in glycine and methionine availability for one-carbon metabolism. These changes were strongly associated with fasting triglycerides and insulin resistance, a key marker of residual CVD risk.

Congenital heart disease (CHD) affects approximately 1% of live births, yet a substantial proportion of cases remain genetically unexplained. Tetralogy of Fallot (TOF) is among the most common cyanotic CHDs. Tandem repeat expansions (TREs) can alter gene regulation and have been implicated in complex cardiac disease, but their contribution to structural CHD remains poorly understood. We performed genome-wide analysis of rare TREs using short-read genome sequencing in 835 individuals with TOF and 386 controls, complemented by PacBio HiFi long-read sequencing, DNA methylation profiling, myocardial RNA sequencing, and fetal human heart single-cell RNA-seq. We further compared TRE-associated genes and biological processes between TOF and a previously characterized cardiomyopathy cohort. We identified 1,043 rare TREs in individuals with TOF, corresponding to 1.25 rare TREs per individual, compared with 0.85 per individual in controls. TOF-associated rare TREs were enriched for GC-rich motifs, more often found in the 5' untranslated regions (UTR; OR = 7.0, p = 2.1 x 10^-2) and splicing regions (OR = 3.0, p = 9 x 10^-4), and located closer to transcription start sites and splice junctions, consistent with a regulatory role. We identified 91 recurrent genic TRE loci, including recurrent 5' UTR TREs absent from controls and TREs in the CHD-associated genes PACS1 and TRIP4. Long-read analysis identified 36 loci at which repeat size was significantly associated with DNA methylation, revealing both expansion-associated hypermethylation and hypomethylation. TRE-associated genes were preferentially expressed in smooth muscle cells, pericytes, and cardiomyocytes in the developing human heart. TRE-associated biological pathways were largely distinct between TOF and cardiomyopathy. Notably, rare TRE burden was higher among individuals without positive clinical genetic testing results. We estimated an excess burden of rare genic TREs of approximately 4.4% in the TOF cohort. Rare TREs represent an underrecognized class of genetic variation contributing to TOF. Their enrichment in regulatory regions, association with locus-specific DNA methylation and transcriptional alterations, and increased burden among genetically unexplained cases support a role for TRE-mediated regulatory dysfunction in CHD pathogenesis and suggest that assessment of tandem repeat variation may improve genetic characterization of TOF.

BACKGROUND: The chromosome 9p21.3 locus is among the strongest genetic risk loci for cardiovascular disease (CVD), yet the regulatory mechanisms underlying this association remain poorly understood. Previous vascular disease studies focused predominantly on the role of this locus in smooth muscle cell (SMC) dysfunction, whereas its potential role in endothelial cells (ECs) remains less well characterized. Here, we sought to identify candidate regulatory variants at 9p21.3, their distal target genes, and effector transcripts that contribute to CVD-related phenotypes in ECs. METHODS: Promoter capture Hi-C was used to map chromatin interactions at 9p21.3 in primary human ascending aortic SMCs (n=6), supplementing the previously obtained ECs (n=16) dataset. To support the regulatory relevance of these interactions, expression quantitative trait locus analysis was performed in 136 vascular biopsies. Variant effects were prioritized in silico using AlphaGenome. The regulatory activity of the prioritized region was validated using CRISPR activation. RESULTS: Chromatin interaction mapping identified a complex regulatory architecture at the 9p21.3 locus involving 19 putative regulatory elements and 15 genes across ECs and SMCs. MIR31HG showed the most recurrent distal promoter connectivity with the 9p21.3 region. Consistent with the chromatin interaction map, expression of MIR31HG transcripts was associated with genetic variation at the 9p21.3 locus. In ECs, the lncRNA MIR31HG, but not miR-31, was responsive to hemodynamic flow. Depletion of MIR31HG in ECs was associated with endothelial activation. Epigenetic tracks and deep learning predictions highlighted an active enhancer element at 9p21.3, which was subsequently validated by CRISPR activation and increased MIR31HG expression, confirming its capacity to regulate MIR31HG over a large genomic distance of approximately 538 kb. CONCLUSIONS: Altogether, these data implicate lncRNA MIR31HG as a likely effector of the 9p21.3 CVD locus, linking the cis-regulatory element and heritable genetic variation in the respective region to endothelial activation through long-range enhancer regulation.

Background: Genetic testing is a Class I recommendation for patients with hypertrophic cardiomyopathy (HCM). As knowledge and frameworks continue to evolve, genetic variant classifications may change with new evidence over time. Classifications rely on evidence sought from publicly available case data, improved classification rules, and gene-disease validity. We evaluated the frequency and reasons for variant reclassification from a large multi-center international HCM registry (Sarcomeric Human Cardiomyopathy Registry; SHaRe). Methods: Participants were clinically evaluated at specialised HCM centres. Genetic variants were sought from the genetic test report, with classifications based on either the initial report, an updated report or some underwent further SHaRe adjudication. All variants were computationally reannotated and reevaluated. Variants underwent expedited curation if no new evidence was present. The remainder underwent full manual curation using accepted criteria and classified as pathogenic/likely pathogenic (P/LP), variant of uncertain significance (VUS) and benign/likely benign (B/LB). Results: Of 12,187 HCM patients, 8,054 (66%) had genetic testing between 1989-2020, and 4,923 (61%) had a variant identified in one of 29 HCM genes (1606 unique variants). Expedited curation was performed for 704 (44%) variants and 902 (56%) underwent manual curation. There were 1275 (79%) variants that retained their classification: 146 B/LB, 660 VUS, and 468 P/LP. While 276 (17%) variants (n=672 patients) were reclassified (n=276), including 73 upgrades: 61 from VUS to P/LP (199 patients), and 12 from B/LB to VUS. There were 203 downgrades: 108 from P/LP to VUS (n=196 patients), and 95 from P/LP or VUS to B/LB. VUS were additionally subclassified: 90 VUS-High, 129 VUS-Mid, 115 VUS-Low. Sub-classification of VUS resulted in less uncertainty, with 369 (40.6%) variants reclassified as VUS-Low or B/LB, indicating a very strong probability of not being HCM associated. Conclusions: Clinically meaningful reclassification occurred in 10% of variants identified in HCM probands. Most VUS were unlikely to be causal, and sub-classification has potential to reduce their burden on clinicians and families. Periodic reevaluation is essential for accurate clinical interpretation.

Dilated cardiomyopathy (DCM) is a leading cause of heart failure and cardiac transplantation, and pathogenic variants in LMNA are a well-established cause of inherited DCM. The LMNA gene encodes nuclear lamins A/C, which maintain nuclear integrity, regulate gene expression and mediate mechanotransduction. Here, we investigated the pathogenic consequences of the NM_170707.4(LMNA):c.274C>T NP_733821.1:p.(Leu92Phe) variant, previously associated with lipodystrophy features, using patient-derived induced pluripotent stem cells, differentiated into cardiomyocytes and show implication of LMNA in sarcomere remodeling and mitochondria efficiency. We generated iPSC lines from two DCM patients carrying LMNA p.Leu92Phe variant in heterozygous form and a healthy parental control. Cardiomyocytes differentiation efficiency was preserved, however, LMNAp.Leu92Phe iPSC-CMs exhibited laminopathies associated phenotypes, such as nuclear shape abnormalities and lamin A/C aggregation. Moreover, in vitro study revealed that LMNA p.Leu92Phe iPSC-CMs alter sarcomere reformation and decrease mitochondrial respiration after cardiomyocyte remodeling, which is associated with a worsening nuclear shape phenotype. Functional analyses highlight defects in calcium handling, thereby explaining arrhythmia and dilated cardiomyopathy features in patients. Our results show that the LMNA p.Leu92Phe variant compromises nuclear lamina integrity and disrupts functional cardiomyocyte properties, particularly during sarcomere remodeling, highlighting the long-term impact of this specific variant in LMNA-associated DCM.

Background: Thoracic aortic aneurysms enlarge silently and can cause fatal aortic dissection without timely surgical repair, underscoring the need for improved approaches to identify individuals at high risk. Rare pathogenic variants in established heritable thoracic aortic disease (HTAD) genes explain only a subset of familial and fewer nonfamilial thoracic aortic disease (TAD) cases. Methods: We performed phenotype-stratified, genome-wide, gene-based rare-variant burden analyses of ultrarare damaging missense and predicted loss-of-function variants. Primary analyses focused on aortic dissection, thoracic aortic aneurysm requiring surgical repair, and their combined phenotype. Broader thoracic aortic aneurysm (TAA) was evaluated as a secondary phenotype. Discovery analyses were conducted in the UK Biobank and All of Us, followed by independent replication in the Penn Medicine BioBank, Mass General Brigham Biobank, and Million Veteran Program. Discovery and replication results were subsequently combined in an overall fixed-effect, inverse-variance-weighted meta-analysis across up to five biobanks. Implicated genes were further evaluated in additional clinically ascertained TAD cohorts and using single-cell transcriptomic data from human thoracic aortic tissue. Results: Discovery analyses identified 80 genes reaching study-wide significance across the prespecified TAD phenotypes. These included six established and two putative HTAD genes. Fourteen genes demonstrated independent replication support and reached study-wide significance in the overall meta-analysis across up to five biobanks, which included more than 10,000 cases and 880,000 controls. The eight novel candidate genes among these were FNDC3B, ROCK1, URM1, SLFN11, ENPP1, CLEC16A, CREM, and VCAN. Associations were strongest for dissection and TAA requiring surgical repair. Four novel associations were driven exclusively by missense variants. FNDC3B was observed in a family with HTAD, while additional variants were identified primarily in sporadic dissection or aortic surgery cohorts, suggesting that other genetic or physiologic factors may influence penetrance. The implicated genes showed cell-type-specific expression patterns in human thoracic aortic tissue. Conclusions: These findings expand the genetic architecture of TAD by identifying eight novel candidate genes and demonstrate the utility of phenotype-stratified rare variant burden analyses across large biobanks for gene discovery.

Brugada syndrome (BrS) is an inherited arrhythmia disorder with limited drug therapy, quinidine being the principal agent. Loss-of-function variants in SCN5A reduce the cardiac sodium current (INa), but the arrhythmogenic imbalance also depends on the transient outward potassium current (Ito). Here we generated human induced pluripotent stem cell-derived cardioids with right-ventricular identity from a patient carrying an SCN5A frameshift variant (p.A665Gfs*16) and characterised them by patch-clamp and optical mapping. BrS cardioids showed 60% lower peak INa, more than doubled Ito, 38% slower conduction and 76% longer spontaneous cycle length. We then tested AR-788, a benzylaminothiazole-benzimidazole carboxamide of the ARumenamide class. In wild-type (WT) cardiomyocytes AR-788 inhibited Ito concentration-dependently (12%, 30% and 42% at 5, 10 and 20 uM; extrapolated IC50 25.4 uM), and at 10 uM it returned BrS Ito to the level of untreated WT cells (21.71 vs 21.48 pA/pF, p = 0.9716) without reducing INa. It also reduced the rapid delayed-rectifier current (IKr) tail current by 40%, a liability requiring formal proarrhythmia profiling. These data identify AR-788 as an Ito-suppressing member of the ARumenamide class and provide proof of concept that a small molecule can correct the potassium-current excess in a human BrS model.

Standard polygenic risk scores capture overall genetic liability to coronary artery disease (CAD) but do not reveal the biological processes contributing to risk in an individual. Here, we applied data-driven latent factor decomposition to 526 genome-wide significant CAD-associated variants, using their associations with 78 CAD-related phenotypic traits. We identified eight genetic components corresponding to cholesterol-enriched lipoproteins, triglyceride-rich lipoproteins, lipoprotein(a), metabolically unhealthy normal weight, obesity, endothelial dysfunction, coagulation and cardiac remodeling. Process-specific polygenic risk scores (pPRSs) captured biological profiles beyond those reflected by conventional risk factors. In UK Biobank (n = 458,905), the Swedish CArdioPulmonary bioImage Study (n = 24,904) and Mass General Brigham Biobank (n = 53,848), pPRSs were consistently associated with clinical and subclinical CAD and showed distinct biomarker, proteomic and comorbidity profiles. These findings establish a framework for biologically resolved genetic CAD risk and may inform process-specific approaches to precision prevention.

Background: Previous studies of genotype-phenotype correlations in hypertrophic cardiomyopathy (HCM) have presented inconsistent conclusions, potentially reflecting small studies and non-uniform phenotyping. Objectives: We aimed to identify genotype-phenotype correlations in sarcomeric variant-positive HCM cardiac magnetic resonance (CMR) imaging and adverse outcome data in the National Heart, Lung, and Blood Institute (NHLBI) HCM Registry. Methods: Of 2750 overall patients, 915 sarcomeric variant-positive ones were subgrouped by genotype. CMR measures of left ventricular (LV) hypertrophy, fibrosis and function, and adverse events, were compared. Findings were meta-analyzed with prior studies from systematic review. Results: Patients with pathogenic variants in thick-filament genes had greater hypertrophy than those in thin-filament genes - maximal LV wall thickness (maxLVWT) (21.7 {+/-} 5.0 vs. 20.0 {+/-} 4.4mm, P<0.01) and indexed LV mass (81.9 {+/-} 26.0 vs. 71.7 {+/-} 13.3g/m2, P<0.001). Of the former, MYBPC3 carriers had greater maxLVWT than MYH7 carriers (22.2 {+/-} 5.2 vs. 20.9 {+/-} 4.5mm, P<0.01) but lower LV ejection fraction (63.1 {+/-} 8.4 vs. 65.3 {+/-} 8.4%, P<0.001). Findings remained significant after covariate adjustment and meta-analysis. 23 (~1%) patients had >1 disease-linked variants with only 3 (~0.11%) carrying >1 pathogenic variants. MYBPC3 carriers had lower risk of a multiple event composite than MYH7 carriers. Conclusions: In the largest CMR-based study to date, we identified significant phenotypic differences that characterize disease-gene subgroups and resolved prior discrepancies through systematic review and meta-analysis. However, carriage of >1 sarcomeric variants did not contribute much to variation in phenotypic severity in the general HCM population due to its rarity.

Genetic testing for cardiomyopathy and arrhythmia (CM/ARRH) provides diagnostic information and informs screening for at-risk relatives. Clinical guidelines recommend genetic testing for these conditions; however, data on how genetic test results influence clinical management recommendations are limited. Here, we determined the frequency of cardiologist-recommended management changes for patients following CM/ARRH genetic testing. This was a retrospective cross-sectional study of patients referred for multigene panel testing between April 2016 and April 2024. Genetically-experienced cardiologists at multicenter academic clinical practices were recruited for participation to complete surveys indicating clinical decision making on patients who had genetic testing. Cases for review were randomly selected to have both positive and non-positive results. Among 249 patients (138 positive, 111 non-positive), 136 (54.6%) received clinical management recommendations for their own or their at-risk relatives? care. Of these, 75 (55.1%) received recommendations for the patient?s own care, most frequently additional diagnostic tests/procedures (n=33). Compared to non-positive results, patients with positive results were more likely to receive recommendations for their own management (66/138, 47.8% vs 9/111, 8.1%; P<0.00001). Patients with positive results in arrhythmogenic cardiomyopathy genes had 263% higher odds of recommended management changes compared to those with TTN (OR=3.63, CI:1.40-9.84, P=0.009). The results from CM/ARRH genetic testing on affected patients influenced cardiologists? medical decision making and management recommendations. Additional research is needed to evaluate how genetic testing for CM/ARRH impact health outcomes.

Background and Aims: Dilated cardiomyopathy (DCM) is a genetically heterogeneous cause of heart failure and sudden cardiac death. Many patients remain without a molecular diagnosis. MAP3K7 encodes TAK1, a serine/threonine kinase important for cardiac homeostasis. MAP3K7 variants are an established cause of syndromic disease, including cardiospondylocarpofacial syndrome (CSCF), in which DCM has been occasionally reported. Here, we demonstrate that MAP3K7 variants can cause apparently isolated DCM, expanding the phenotypic spectrum of MAP3K7-related disorders. Methods: We compiled four orthogonal lines of human genetic evidence: de novo variation in paediatric cardiomyopathy; common variant association with adult DCM; familial segregation; and rare variant enrichment in DCM cases, together with functional categorisation of rare variants. Results: In 117 paediatric cardiomyopathy trios from the 100,000 Genomes Project, two probands harboured rare de novo MAP3K7 missense variants, significantly more than expected (Bonferroni-adjusted p=0.036). Independent GWAS implicated MAP3K7 as a susceptibility locus for adult DCM. Across global DCM cohorts, we identified families harbouring rare MAP3K7 variants, including one with segregation in nine affected relatives. Rare damaging non-truncating variants were enriched in DCM cases, while truncating variants were associated with DCM in the Genomics England cohort and increased left ventricular volumes in UK Biobank. DCM-associated variants reduced TAK1 kinase activity, supporting a loss-of-function mechanism consistent with CSCF-associated alleles. Conclusion: Multiple independent lines of evidence establish an association between MAP3K7 loss of function variants and DCM. Several affected individuals lacked overt syndromic features, demonstrating that MAP3K7-related disease may present as apparently isolated DCM across the lifespan and supporting inclusion of MAP3K7 in DCM diagnostic pipelines.

Polygenic risk scores (PRS) have emerged as promising tools for stratifying inherited disease risk, yet their translation into clinical practice is constrained by a critical and frequently unmet requirement: demonstration that scores derived in one cohort retain discriminatory value when applied independently in a different population. For suspected familial hypercholesterolemia (FH), a substantial proportion of patients that meet clinical criteria still test negative for a monogenic cause. These patients are presumed to carry polygenic LDL-C burden, yet PRS validation is still scarce. Here, we evaluated a published hypercholesterolemia PRS (PGS000936) spanning 5,386 genome-wide loci. We tested the score in 117 monogenic-negative hypercholesterolemia cases and 496 controls from the German general population genotyped on the Illumina Global Screening Array v3.0, with imputation to approximately 11 million variants. The score was applied without retraining, using externally derived {beta}-coefficients. The PRS clearly distinguished cases from controls (p < 2x10-16), with a mean PRS of 0.97 in cases versus 0.52 in controls. Decile analysis revealed a seven-fold increase in odds of hypercholesterolemia in the top 10% of the distribution (OR 7.55; 95% CI 4.36-13.07; p < 0.0001). In 94 cases for which clinical data was available, higher PRS was associated with significantly higher LDL-C levels before treatment. Importantly, the PRS distribution in the German control cohort was shifted relative to that of the control cohort in the initial study, suggesting that population-matched calibration is required for accurate odds ratio estimation and proper interpretation of PRS values. These findings show that the published hypercholesterolemia PRS (PGS000936) can effectively stratify risk and identify individuals with a high genetic burden in a real-world German clinical setting, supporting its clinical utility when appropriately calibrated for the local population.

Aortic stenosis (AS) is a heterogeneous disease of aging characterized by valvular calcification and distinct structural, electrical, and hemodynamic remodeling that are incompletely captured by any single diagnostic measure. Here we show that three AI-derived digital biomarkers resolve AS-related remodeling into complementary structural (cine-CMR Digital AS Severity Index, DASSi), electrical (AI-ECG), and hemodynamic (phase-contrast CMR peak aortic velocity) axes. Among 68,714 UK Biobank participants, all three biomarkers were independently associated with prevalent AS and prospectively predicted aortic valve replacement. Genetic and transcriptomic analyses of the digital phenotypes revealed partially distinct, heritable architectures: peak aortic velocity aligned closely with clinical AS genetics, whereas DASSi and AI-ECG defined a shared myocardial-remodeling axis largely independent of clinical AS susceptibility. These findings support AS as a multidimensional remodeling syndrome and establish a novel digital phenotyping framework for dissecting complex cardiovascular disease into complementary, biologically informative axes.

Observational studies suggest an association between COVID-19 and acute myocardial infarction (AMI), however, whether this relationship is causal remains unclear. We conducted a multi-ancestry Mendelian randomization (MR) study across European, East Asian, South Asian, and African populations, evaluating three COVID-19 phenotypes: very severe COVID-19, hospitalized COVID-19, and general infection association with AMI. GWAS summary statistics were obtained from the COVID-19 Host Genetics Initiative Round 7 and UK Biobank/Biobank Japan for AMI. Inverse-variance weighted (IVW) MR was the primary method, with fixed- or random-effects models selected according to heterogeneity test. MR-Egger, weighted median and weighted mode were conducted as sensitivity analyses. In European ancestry, genetic liability to very severe COVID-19 and hospitalized COVID-19 was slightly inversely associated with AMI risk, but without statistical significances across sensitivity analyses. Hospitalized COVID-19 showed a suggestive but non-significant inverse association in South Asian ancestry. No significant associations were identified in East Asian or African ancestries. Our findings did not support a robust causal association between COVID-19 susceptibility or severity and AMI risk across ancestries, suggesting that the observed cardiovascular burden may be driven more by acute pathophysiological mechanisms than shared genetic architecture.

Selenoproteins are a specialised group of proteins that incorporate selenium, an essential micronutrient, in the form of selenocysteine. The SECIS binding protein 2 (SBP2), encoded by SECISBP2, is a crucial component of the selenocysteine incorporation machinery. SECISBP2 deficiency compromises selenoprotein synthesis, and its knockout causes embryonic lethality in mice. Selenium is critical to cardiac function, and nutritional deficiency causes Keshan disease, a progressive cardiomyopathy. Biallelic variants in SECISBP2 cause pleiotropic phenotypes including abnormal thyroid hormone metabolism, neurodevelopmental disorders and aortic aneurysms. No reported phenotypes to date include cardiomyopathy. We report a consanguineous South Asian family with a history of perinatal deaths due to progressive cardiomyopathy and intractable arrhythmias with a rare homozygous loss-of-function splice site variant in SECISBP2. The SECISBP2 c.1303-2A>G variant was homozygous in four affected offspring and heterozygous in the parents. One child without cardiac disease did not carry this variant. RNA sequencing confirmed that almost all transcripts would undergo nonsense-mediated decay. Further, we observed a pronounced decrease in GPX1 and SELENOH selenoprotein mRNA, as well as a large decrease in SELENOH, GPX1, GPX3 and GPX4 cardiac protein abundance in homozygotes, a molecular hallmark of SECISBP2 deficiency. Notably, we observed a >12-fold decrease in cardiac GPX4, a key selenoprotein that suppresses lipid peroxidation and ferroptosis, suggesting a possible ferroptosis-mediated mechanism for heart failure. Our analysis suggests that c.1303-2A>G is likely the most damaging homozygous variant discovered to date. For the first time, we show that SECISBP2 is essential for human life, with almost complete loss-of-function causing a lethal perinatal cardiomyopathy characterised by pronounced cardiac selenoprotein loss.