European Genome-wide Association Studies Research Articles

Brugada syndrome in Japan and Europe: a genome-wide association study reveals shared genetic architecture and new risk loci.

Brugada syndrome (BrS) is an inherited arrhythmia with a higher disease prevalence and more lethal arrhythmic events in Asians than in Europeans. Genome-wide association studies (GWAS) have revealed its polygenic architecture mainly in European populations. The aim of this study was to identify novel BrS-associated loci and to compare allelic effects across ancestries. A GWAS was conducted in Japanese participants, involving 940 cases and 1634 controls, followed by a cross-ancestry meta-analysis of Japanese and European GWAS (total of 3760 cases and 11 635 controls). The novel loci were characterized by fine-mapping, gene expression, and splicing quantitative trait associations in the human heart. The Japanese-specific GWAS identified one novel locus near ZSCAN20 (P = 1.0 × 10-8), and the cross-ancestry meta-analysis identified 17 association signals, including six novel loci. The effect directions of the 17 lead variants were consistent (94.1%; P for sign test = 2.7 × 10-4), and their allelic effects were highly correlated across ancestries (Pearson's R = .91; P = 2.9 × 10-7). The genetic risk score derived from the BrS GWAS of European ancestry was significantly associated with the risk of BrS in the Japanese population [odds ratio 2.12 (95% confidence interval 1.94-2.31); P = 1.2 × 10-61], suggesting a shared genetic architecture across ancestries. Functional characterization revealed that a lead variant in CAMK2D promotes alternative splicing, resulting in an isoform switch of calmodulin kinase II-δ, favouring a pro-inflammatory/pro-death pathway. This study demonstrates novel susceptibility loci implicating potentially novel pathogenesis underlying BrS. Despite differences in clinical expressivity and epidemiology, the polygenic architecture of BrS was substantially shared across ancestries.

Causality of Genetically Determined Metabolites on Chronic Kidney Disease: A Two-Sample Mendelian Randomization Study In Silico.

Introduction: Chronic kidney disease (CKD) is associated with metabolic disorders. However, the evidence for the causality of circulating metabolites to promote or prevent CKD is still lacking. Methods: The two-sample Mendelian randomization (MR) analysis was conducted to evaluate the latent causal relationship between the genetically proxied 486 blood metabolites and CKD. Genome-wide association study (GWAS) data for exposures were derived from 7824 European GWAS on metabolite levels, which have been extensively utilized in the medical field to elucidate the mechanisms underlying disease onset and progression. The random inverse variance weighted (IVW) is the primary analysis for causality analysis while MR-Egger and weighted median as complementary analyses. For the further identification of metabolites, reverse MR and linkage disequilibrium score regression were performed for further evaluation. The drug target for N-acetylornithine was subsequently supplemented into the analysis, with MR and colocalization analysis being utilized. Key metabolic pathways were identified via MetaboAnalyst 4.0 (https://www.metaboanalyst.ca/) online website. Results: N-acetylornithine was identified as a reliable metabolite that increases the susceptibility to estimated glomerular filtration rate (eGFR) decrease (β = 0.047; 95% confidence interval: -0.068 to -0.026; PIVW = 1.5E-5). The "glyoxylate and dicarboxylate metabolism" pathway showed significant relevance to CKD development (P = 6E-4), whereas the "glycine, serine, and threonine metabolism" pathway was also recognized as associated with CKD by general practitioners (P = 7E-4). Colocalization analysis revealed a robust genetic link between N-acetylornithine and both CKD and eGFR, with 85.1% and 99.4% colocalization rates, respectively. IVW-MR analysis substantiated these findings with a significant positive association for CKD (odds ratio = 1.43, P = 4.7E-5) and a negative correlation with eGFR (b = -0.04, P = 1.13E-31). Conclusions: MR was utilized to explore the potential causal links between 61 genetic serum metabolites and CKD. N-acetylornithine and NAT8 were further explored as a potential therapeutic target for CKD treatment.

Exploring causal correlations between inflammatory cytokines and knee osteoarthritis: a two-sample Mendelian randomization.

Knee osteoarthritis (KOA) and certain inflammatory cytokines (such as interleukin 1 [IL-1] and tumor necrosis factor alpha [TNF-a]) are related; however, the causal relationship remains unclear. Here, we aimed to assess the causal relationship between 41 inflammatory cytokines and KOA using Mendelian randomization (MR). Two-sample bidirectional MR was performed using genetic variation data for 41 inflammatory cytokines that were obtained from European Genome-Wide Association Study (GWAS) data (n=8293). KOA-related genetic association data were also obtained from European GWAS data (n=40,3124). Inverse variance weighting (IVW), MR, heterogeneity, sensitivity, and multiple validation analyses were performed. Granulocyte colony-stimulating factor (G-CSF) or colony-stimulating factor 3 (CSF-3) levels were negatively associated with the risk of developing KOA (OR: 0.93, 95%CI:0.89-0.99, P=0.015). Additionally, macrophage inflammatory protein-1 alpha (MIP-1A/CCL3) was a consequence of KOA (OR: 0.72, 95%CI:0.54-0.97, P=0.032). No causal relationship was evident between other inflammatory cytokines and KOA development. This study suggests that certain inflammatory cytokines may be associated with KOA etiology. G-CSF exerts an upstream influence on KOA development, whereas MIP-1A (CCL-3) acts as a downstream factor.

Essential Nutrients and White Matter Hyperintensities: A Two-Sample Mendelian Randomization Study.

Stroke and dementia have been linked to the appearance of white matter hyperintensities (WMHs). Meanwhile, diffusion tensor imaging (DTI) might capture the microstructural change in white matter early. Specific dietary interventions may help to reduce the risk of WMHs. However, research on the relationship between specific nutrients and white matter changes is still lacking. We aimed to investigate the causal effects of essential nutrients (amino acids, fatty acids, mineral elements, and vitamins) on WMHs and DTI measures, including fraction anisotropy (FA) and mean diffusivity (MD), by a Mendelian randomization analysis. We selected single nucleotide polymorphisms (SNPs) associated with each nutrient as instrumental variables to assess the causal effects of nutrient-related exposures on WMHs, FA, and MD. The outcome was from a recently published large-scale European Genome Wide Association Studies pooled dataset, including WMHs (N = 18,381), FA (N = 17,663), and MD (N = 17,467) data. We used the inverse variance weighting (IVW) method as the primary method, and sensitivity analyses were conducted using the simple median, weighted median, and MR-Egger methods. Genetically predicted serum calcium level was positively associated with WMHs risk, with an 8.1% increase in WMHs risk per standard deviation unit increase in calcium concentration (OR = 1.081, 95% CI = 1.006-1.161, p = 0.035). The plasma linoleic acid level was negatively associated with FA (OR = 0.776, 95% CI = 0.616-0.978, p = 0.032). Our study demonstrated that genetically predicted calcium was a potential risk factor for WMHs, and linoleic acid may be negatively associated with FA, providing evidence for interventions from the perspective of gene-environment interactions.

Investigation of the causal relationship between inflammatory bowel disease and type 2 diabetes mellitus: a Mendelian randomization study.

Background: Type 2 diabetes mellitus (T2DM) and inflammatory bowel disease (IBD) have been associated, according to various epidemiological research. This study uses Mendelian randomization (MR) to investigate the causal link between T2DM and IBD. Methods: To investigate the causal relationship between IBD and T2DM risk using European population data from the genome-wide association study (GWAS) summary datasets, we constructed a two-sample MR study to evaluate the genetically predicted impacts of liability towards IBD outcomes on T2DM risk. As instrumental variables (IVs), we chose 26 single nucleotide polymorphisms (SNPs) associated with IBD exposure data. The European T2DM GWAS data was obtained from the IEU OpenGWAS Project database, which contains 298,957 cases as the outcome data. The causal relationship between T2DM and IBD using a reverse MR analysis was also performed. Results: The two-sample MR analysis, with the Bonferroni adjustment for multiple testing, revealed that T2DM risk in Europeans is unaffected by their IBD liability (odds ratio (OR): 0.950-1.066, 95% confidence interval (CI): 0.885-1.019, p = 0.152-0.926). The effects of liability to T2DM on IBD were not supported by the reverse MR analysis either (OR: 0.739-1.131, 95% confidence interval (CI): 0.651-1.100, p = 0.058-0.832). MR analysis of IBS on T2DM also have no significant causal relationship (OR: 0.003-1.007, 95% confidence interval (CI): 1.013-5.791, p = 0.069-0.790). FUMA precisely mapped 22 protein-coding genes utilizing significant SNPs of T2DM acquired from GWAS. Conclusion: The MR study showed that the existing evidence did not support the significant causal effect of IBD on T2DM, nor did it support the causal impact of T2DM on IBD.

Revisiting an old relationship: the causal associations of the ApoB/ApoA1 ratio with cardiometabolic diseases and relative risk factors-a mendelian randomization analysis.

It has been confirmed that the ApoB/ApoA1 ratio is closely associated with the incidence of cardiometabolic diseases (CMD). However, due to uncontrolled confounding factors in observational studies, the causal relationship of this association remains unclear. In this study, we extracted the ApoB/ApoA1 ratio and data on CMD and its associated risk factors from the largest European Genome-Wide Association Study. The purpose was to conduct Mendelian Randomization (MR) analysis. The causal relationship between the ApoB/ApoA1 ratio and CMD was evaluated using both univariable and multivariable MR analyses. Furthermore, bidirectional MR analysis was performed to estimate the causal relationship between the ApoB/ApoA1 ratio and risk factors for CMD. The final verification confirmed whether the ApoB/ApoA1 ratio exhibits a mediating effect in CMD and related risk factors. In terms of CMD, a noteworthy correlation was observed between the increase in the ApoB/ApoA1 ratio and various CMD, including ischemic heart disease, major adverse cardiovascular events, aortic aneurysm, cerebral ischemic disease and so on (all PFDR<0.05). Meanwhile, the ApoB/ApoA1 ratio was significantly associated with CMD risk factors, such as hemoglobin A1c, fasting insulin levels, waist-to-hip ratio, sedentary behavior, and various others, demonstrating a notable causal relationship (all PFDR<0.05). Additionally, the ApoB/ApoA1 ratio played a mediating role in CMD and relative risk factors. This MR study provides evidence supporting the significant causal relationship between the ApoB/ApoA1 ratio and CMD and its risk factors. Moreover, it demonstrates the mediating effect of the ApoB/ApoA1 ratio in CMD and its risk factors. These findings suggest that the ApoB/ApoA1 ratio may serve as a potential indicator for identifying the risk of developing CMD in participants.

GWAS for systemic sclerosis identifies six novel susceptibility loci including one in the Fcγ receptor region

Here we report the largest Asian genome-wide association study (GWAS) for systemic sclerosis performed to date, based on data from Japanese subjects and comprising of 1428 cases and 112,599 controls. The lead SNP is in the FCGR/FCRL region, which shows a penetrating association in the Asian population, while a complete linkage disequilibrium SNP, rs10917688, is found in a cis-regulatory element for IRF8. IRF8 is also a significant locus in European GWAS for systemic sclerosis, but rs10917688 only shows an association in the presence of the risk allele of IRF8 in the Japanese population. Further analysis shows that rs10917688 is marked with H3K4me1 in primary B cells. A meta-analysis with a European GWAS detects 30 additional significant loci. Polygenic risk scores constructed with the effect sizes of the meta-analysis suggest the potential portability of genetic associations beyond populations. Prioritizing the top 5% of SNPs of IRF8 binding sites in B cells improves the fitting of the polygenic risk scores, underscoring the roles of B cells and IRF8 in the development of systemic sclerosis. The results also suggest that systemic sclerosis shares a common genetic architecture across populations.

Coffee Intake, Plasma Caffeine Levels, and Kidney Function: Two-Sample Mendelian Randomization Among East Asian and European Ancestries

IntroductionPrevious Mendelian randomization (MR) studies for the coffee-kidney association have reported inconsistent relationships in European populations and never examined mediators of this association. We aimed to evaluate this causal relationship using two-sample MR among both East Asian and European ancestries and to explore underlying mechanisms using plasma caffeine levels. MethodsAmong East Asians, the largest genome-wide association study (GWAS) results for coffee intake, plasma caffeine levels, and kidney outcomes were obtained from 152,634, 8,940, and 47,070 Japanese adults. Among Europeans, summary statistics were acquired from European GWAS with 428,860, 7,719, and 564,470 adults for each trait. We applied different MR methods (inverse-variance weighted with random effects, weighted median, weighted mode, and MR-Egger). ResultsAfter excluding possible pleiotropic variants, among East Asian ancestry, drinking an extra coffee intake per week showed a protective association on eGFRcre (β=0.077; 95% CI=0.003 to 0.150). Analysis in European ancestry also showed a causal relationship between drinking an extra coffee intake per day and eGFRcre (β=0.052; 95% CI=0.027 to 0.078). These results were consistent across different MR methods accounting for invalid instruments. Higher plasma caffeine levels were associated with lower eGFRcre among both East Asian (β=–0.071; 95% CI=–0.137 to –0.006) and European ancestries (β=–0.048; 95% CI=–0.057 to –0.040). ConclusionsOur cross-ancestry MR study found beneficial effects of coffee intake on eGFRcre. However, given the possible adverse effects of plasma caffeine levels on eGFRcre, results interpretation should be carefully considered and further investigations on non-caffeine and biological pathways are needed.

The causal effect of cytokine cycling levels on osteoarthritis: a bidirectional Mendelian randomized study.

Osteoarthritis (OA) is the most prevalent joint disease globally, serving as a primary cause of pain and disability. However, the pathological processes underlying OA remain incompletely understood. Several studies have noted an association between cytokines and OA, yet the causal link between them remains ambiguous. This study aims to identify cytokines potentially causally related to OA using Mendelian randomization (MR) analysis, informing early clinical diagnosis and treatment decisions. We conducted a genome-wide association study (GWAS) on 12 OA traits involving 177,517 cases and 649,173 controls from 9 international cohorts. For discovery MR analysis, we used 103 cytokines from two European populations as instrumental variables (IVs). Concurrently, another European population OA GWAS database (36,185 cases and 135,185 controls) was used to replicate MR analysis, employing the inverse variance weighted (IVW) method as the primary analytic approach. Additional methods tested included MR Egger, Weighted median, and Weighted mode. We merged the MR findings through meta-analysis. Heterogeneity testing, level pleiotropy testing (MR Egger intercept test and MRPRESSO), and sensitivity analysis via Leave One Out (LOO) were conducted to verify result robustness. Lastly, reverse MR analysis was performed. The meta-analysis merger revealed a correlation between CX3CL1 cycle levels and increased OA risk (OR=1.070, 95% CI: 1.040-1.110; P<0.010). We also observed associations between MCP4 (OR=0.930, 95% CI: 0.890-0.970; P<0.010) and CCL25 (OR=0.930, 95% CI: 0.890-0.970; P<0.010) with reduced OA risk. The sensitivity analysis results corroborate the robustness of these findings. Our MR analysis indicates a potential causal relationship between CX3CL1, MCP4, CCL25, and OA risk changes. Further research is warranted to explore the influence of cytokines on OA development.

Genetically predicted 486 blood metabolites concerning risk of systemic lupus erythematosus: a Mendelian randomization study

Metabolic abnormalities constitute a significant characteristic of systemic lupus erythematosus (SLE). We utilised a two-sample Mendelian randomisation (MR) study to evaluate the potential causal association between 486 blood metabolites and SLE. Exposure data at the metabolite level were extracted from 7824 European Genome-wide association studies (GWAS). Preliminary analysis utilised SLE GWAS data from FinnGen. The primary method for causal analysis relied on random inverse variance weighting (IVW). To ensure robustness, sensitivity analyses included the Cochran Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out analysis. Steiger testing and linkage disequilibrium score regression were employed to validate the identified metabolites. This study identified 12 metabolites, comprising six known chemical structures: 1,5-anhydroglucitol(1,5-AG) [odds ratio (OR) = 0.100, 95% confidence interval (CI): 0.015–0.773, P = 0.027), gamma-glutamylthreonine (OR = 0.077, 95% CI: 0.010–0.574, P = 0.012), 5-dodecenoate(12:1n7) (OR = 0.205, 95% CI: 0.061–0.685, P = 0.010), linoleoylglycerophosphoethanolamine * (OR = 0.159, 95% CI: 0.027–0.933, P = 0.044), erythrose (OR = 88.331,95% CI:1.098–63.214, P = 0.040) and 1-, adrenate (22:4n6) (OR = 9.876, 95% CI: 1.753–55.639, P = 0.001)]. Additionally, we found associations between SLE and six unknown chemical structures: X-06351 (OR = 0.071, 95% CI: 0.006–0.817, P = 0.034), X-10810 (OR = 4.268 95% CI: 1.260–14.459, P = 0.020), X-11412 (OR = 5.418 95% CI: 1.068–27.487, P = 0.041), X-11905 (OR = 0.551, 95%CI: 0.304–0.997, P = 0.049), X-12038 (OR = 0.178 95%CI: 0.032–0.988, P = 0.045), X-12217 (OR = 0.174 95%CI: 0.044–0.680, P = 0.014). This study offers evidence supporting a causal relationship between SLE and 12 circulating metabolites, six of which have known chemical structures and six that remain unidentified. These findings introduce a new perspective for further exploration of SLE mechanisms.

Appraising the role of circulating concentrations of micronutrients in attention deficit hyperactivity disorder: a Mendelian randomization study

Previous observational researches have discovered a connection between circulating concentrations of micronutrients and attention deficit hyperactivity disorder (ADHD). However, the results may be influenced by confounding factors and reverse causation. This study aims to explore the causal relationship between circulating concentrations of micronutrients and ADHD using Mendelian randomization (MR). In a two-sample MR context, we used summary data from the major European genome-wide association studies (GWAS) for these illnesses to assess the genetically anticipated effects of circulating concentrations of micronutrients on ADHD risk. In order to achieve this, we took single nucleotide polymorphisms (SNPs) from the GWAS that were highly related with concentrations of nine micronutrients. The corresponding data for ADHD were extracted from the Psychiatric Genomics Consortium. Inverse-variance weighted (IVW) method was used as the main MR analysis, and the reliability of the study’s conclusions was assessed using sensitivity analyses. Our MR analyses showed that the copper level may be associated with a reduced risk of ADHD. However, the significance of the research results is weak. There were no clear relationships between other micronutrients and ADHD. Our sensitivity studies confirmed the findings of the primary IVW MR analyses. According to this study, there may be some association between copper level and ADHD, but the significance of the research results is weak, and it is recommended that copper level should be used as a long-term monitoring indicator for further research. The results provide a new idea for the further study of ADHD, and provide guidance for the prevention and treatment of ADHD.

Genome‐wide Association Study Meta‐analysis of Neurofilament light (NfL) levels in blood reveals novel loci related to neurodegeneration

AbstractBackgroundNeurofilament light chain (NfL) levels in circulation have been established as a sensitive biomarker of neuro‐axonal damage across a range of neurodegenerative disorders. Elucidation of the genetic architecture of blood NfL levels and its genetic correlation with neurological traits could therefore provide new insights into shared molecular mechanisms underlying neurodegenerative disorders.MethodTo identify the genetic variations underlying blood NfL levels, we conducted an ancestry‐specific meta‐analyses of genome‐wide association studies (GWAS) based on 18,532 participants from 11 cohorts of European and 1142 participants (3 cohorts) of African‐American ancestry. In the post‐GWAS analyses, we performed expression quantitative trait loci (eQTL) analysis, LD‐regression, and genetic risk score (GRS) association analysis with neurological traits.ResultIn the European ancestry GWAS meta‐analysis, we identified two genome‐wide significant (P&lt; 5×10−8) loci at 16p12 (UMOD), and 17q24 (SLC39A11). In the African‐American ancestry GWAS meta‐analysis, we identified three novel loci at 1q43 (FMN2), 12q14, and 12q21. Genetic correlation based on the European ancestry meta‐analysis with neurological traits showed a strong genetic correlation of NfL with Alzheimer’s disease (AD) (rg = 0.32, P = 1.74×10−6), total‐tau (rg = 2.01, P = 1.03×10−6), amyloid‐beta (Aβ)‐40 (rg = 0.80, P = 6.92×10−6),and Aβ‐42 (rg = 1.03, P = 4.39×10−5). A higher genetic risk score based on NfL‐associated genetic variants was also related to increased plasma levels of total‐tau (P = 1.97×10−4), Aβ‐ 40 (P = 2.24×10−5), Aβ‐42 (P = 2.92×10−4) in the Rotterdam Study.ConclusionThis large‐scale GWAS meta‐analysis revealed multiple novel genetic loci of NfL levels in blood in participants from European and African‐American ancestry. Significant genetic correlation of genes underlying NfL with AD, Aβ‐42, and total‐tau may indicate a common underlying pathway of neurodegeneration.

Evaluation of the Causal Effects of COVID‐19 on Alzheimer’s Disease: LD Score Regression Analysis and Mendelian Randomization Study

AbstractBackgroundCOVID‐19 is an acute respiratory infection that is frequently followed by short‐ or long‐term neurological abnormalities, and may increase the risk of developing Alzheimer’s disease (AD). However, the genetic and biological mechanisms underlying this risk are poorly understood. Utilizing publicly available large genome‐wide association studies (GWAS), we explored the possible causal effects of three different COVID‐19 phenotypes on AD.MethodCOVID‐19 GWAS data from European cohorts were obtained from the Host Genetics Initiative website in its most recent release (HGI7‐EUR) with three phenotypes: 1) critically ill COVID‐19 (case/ctrl: 13,769/1,072,442); 2) hospitalized COVID‐19 (case/ctrl: 32,519/2,062,805); 3) regular COVID‐19 infection (case/ctrl: 2,475,240/12,597,856). European AD GWAS data were retrieved from Jansen et al.’s study (case/ctrl: 71,880/ 383,378). The linkage disequilibrium score regression (LDSC) and Mendelian randomization (MR) methods were used to analyze the genetic correlation and possible causal effects among the three COVID‐19 phenotypes and AD.ResultLDSC indicated that AD had significant positive correlations with the critically ill COVID‐19 (FDR = 0.021, z = 2.45, rg = 0.224) and hospitalized COVID‐19 (FDR = 0.020, z = 2.71, rg = 0.241) phenotypes, but not regular COVID‐19 infection (FDR = 0.133). On the other hand, MR with the fixed‐effects inverse variance weighted method indicated that regular COVID‐19 had some causal effect on AD (P = 0.019, beta = 0.032). Marginal causal effects on AD were also found from critical COVID‐19 (P = 0.072, beta = 0.008) and hospitalized COVID‐19 (P = 0.082, beta = 0.013). In addition, MR with weighed mode method showed significant effects on AD from three COVID‐19 phenotypes (P = 0.040‐0.003), while MR‐Egger method did not show any significance between the two diseases.ConclusionUsing LDSC and MR approaches, our preliminary data identified a genetic correlation between hospitalized and critically ill COVID‐19 phenotypes and AD, and possible causal effects on AD through genetic variants shared with standard COVID‐19 infection. With the continuing COVID‐19 epidemic and the high comorbidity and mortality of AD from COVID‐19 infection, our observations emphasize the urgency of understanding the overlapping genetic risk for the two diseases. Further studies might shed light on the long‐term neurological influence of COVID‐19 and further provide strategies for disease intervention against COVID‐19 and AD.

Exploring causal association between circulating inflammatory cytokines and functional outcomes following ischemic stroke: A bidirectional Mendelian randomization study.

Previous observational studies have indicated correlations between various inflammatory cytokines and functional outcomes following ischemic stroke (IS); however, the causality remains unclear. We aimed to further evaluate the causal association between 41 circulating inflammatory cytokines and functional outcomes following IS. Two-sample bidirectional Mendelian randomization (MR) analysis was used in this study. The genetic variation of 41 circulating inflammatory cytokines were derived from genome-wide association study (GWAS) data of European ancestry (n = 8293). The corresponding genetic association of functional outcomes following IS were derived from European ancestry GWAS data (n = 6021). Inverse variance weighted (IVW) analysis showed that genetically predicted increased levels of regulation and activation in normal T-cell expression and secretion factor (RANTES/CCL5) and eosinophilic chemotactic factor (EOTAXIN/CCL11) were positively correlated with the increased adverse functional outcomes (modified Rankin Scale [mRS≥3] following IS (OR: 1.40, 95% CI: 1.002-1.96, p = 0.049; OR: 1.33, 95% CI: 1.15-1.54, p = 0.0001). Interleukin 18 (IL-18) level might be the downstream consequence of adverse functional outcomes following IS (β: -0.09, p = 0.039). Other inflammatory cytokines and functional outcomes following IS did not appear to be causally related. This study suggests a causality between inflammation and adverse functional outcomes following IS. RANTES (CCL5) and EOTAXIN (CCL11) may be the upstream factors of adverse functional outcomes following IS, while IL-18 may be the downstream effect of adverse functional outcomes following IS. Whether these cytokines can be used to predict or improve adverse functional outcomes after IS requires further researches.

Population-specific and cross-ancestry genome-wide association study identifies shared genetic architecture and 6 new risk loci including CAMK2D associated for Brugada syndrome

Abstract Introduction The Brugada syndrome (BrS) is an inherited arrhythmia characterized by coved-type ST-segment elevation in the right precordial leads and an increased risk for sudden cardiac death. Genome-wide association studies (GWAS) of BrS, mainly performed in European ancestry, have illustrated its complex genetic architecture as an polygenic disease besides a monogenic trait due to mutations in the major responsible cardiac sodium channel gene SCN5A. Clinical manifestations of BrS including the disease prevalence and the incidence of sudden death are known to be variable between Asian and European populations, however, its underlying mechanisms are largely unknown. Objectives We aimed to identify novel BrS-associated loci and to assess ancestry-dependent genetic heterogeneity that may underlie the variable clinical manifestations of BrS patients across different populations. Methods We performed a genome-wide meta-analysis of BrS in the Japanese ancestry (940 cases and 1,634 controls), followed by a cross-ancestry meta-analysis of Japanese and European GWAS (total of 3,760 cases and 11,635 controls) to identify novel risk loci and compared the allelic effects between two ancestries. We characterized the novel loci based on fine-mapping of potential causal variants, and expression and splicing quantitative trait associations using the Genotype-Tissue Expression (GTEx) database. Results The Japanese-specific genome-wide meta-analysis identified a novel association signal near the ZSCAN20 (lead variant, rs2336244; P=1.0E-08) besides previously reported 4 association signals at the SCN5A-SCN10A and HEY2 loci. Cross-ancestry genome-wide meta-analysis identified 17 association signals including 6 novel loci. The effect directions were consistent for 94.1% of the variants (16 of 17; P for sign test = 0.00027) and their allelic effects were highly correlated across ancestries (Pearson’s R=0.91 [P=2.9E-07]). The genetic risk score (GRS) derived from European-ancestry GWAS of BrS was significantly associated with the risk of BrS in the Japanese populations (odds ratio, 2.12 [95% confidence interval, 1.94–2.31]; P=1.2E-61), suggesting the shared genetic architecture across ancestries. The functional characterization of the 6 novel loci showed that one lead SNP on CAMK2D promotes an alternative splicing resulting in an isoform switch of calmodulin kinase II that favors up-regulation of the pro-inflammatory isoform δ9 and down-regulation of the pro-survival isoform δ3. Conclusions Our results identified 6 novel susceptible loci associated with BrS and revealed shared genetic architecture across ancestries.GWAS Manhattan plotShared genetic architecture

Comparison of clinical and genetic risk model based on ethnicity for ischemic stroke after atrial fibrillation catheter ablation

Abstract Introduction CHA₂DS₂-VASc score (CVS) is widely used to estimate the risk of stroke in atrial fibrillation (AF) patients. However, CVS does not include genetic risk, and the risk model for stroke dose not well developed after AF catheter ablation (AFCA). We explored the clinical and genetic risks for ischemic stroke (IS) and compared the difference in prediction power according to ethnicity. Methods We used available genome-wide association study (GWAS) data in European (34217 IS, 406111 controls) and Asian (22664 IS, 152022 controls) to develop polygenic risk score (PRS) for IS in 2897 independent Korean AF patients (Median 60 [IQR 52, 67] years, male 74.0%, paroxysmal AF 66.3%, anticoagulation rate 60% in 1367 patients over 2 points of CVS) who underwent the AFCA. The patients with IS within 2 weeks after the AFCA were excluded. In the independent AF cohort during the median 50 [IQR 28-94] months follow-up, 48 experienced the IS after the AFCA. We developed two different PRS derived from European and Asian GWAS data and then two different CVS-combined PRS models in the independent cohort. After including SNPs with p-value &amp;lt;5e-8 in the development cohort, rs635634 and rs671 were used in the CVS-combined European PRS (CVS-EPRS) and CVS-combined Asian PRS (CVS-APRS) model, respectively in the independent cohort. We compared the C index of risk models to investigate the prediction power for the IS. Results The CVS was significantly higher in the patients with IS than in their counterparts (3.0 IQR [1.0, 4.0 vs. 1.0 [1.0, 2.0], p&amp;lt;0.001). The overall C index was 0.716 in CVS alone model, 0.711 in the CVS-EPRS model, and 0.725 CVS-APRS model. For predicting 1-year IS after the AFCA, the CVS-APRS model improved the C index as compared to CVS alone model (0.834 vs. 0.813, p=0.037). For predicting 3-year IS after the AFCA, the C-index was higher in the CVS-APRS model as compared to the CVS-EPRS model (0.746 vs. 0.721, p=0.030) Conclusions In AF patients with the AFCA, genetic polymorphism with clinical risk factors contributed to predict the 1-year IS. However, ethnicity might be an important factor in adapting genetic contributions to predicting IS.Study flow chartTime dependent ROC curve

A bidirectional Mendelian randomization study of sarcopenia-related traits and inflammatory bowel diseases.

There is increasing evidence pointing to a close relationship between sarcopenia and inflammatory bowel disease. However, it remains unclear whether or in which direction causal relationships exist, because these associations could be confounded. We conducted a two-sample bidirectional mendelian randomization analysis using data from European genome-wide association studies of the appendicular lean mass(n = 450,243), walking pace(n = 459,915), grip strength (left hand, n = 461,026; right hand, n = 461,089), inflammatory bowel disease (25,042 patients and 34,915 controls), ulcerative colitis (12,366 patients and 33,609 controls), and Crohn's disease (12,194 patients and 28,072 controls) to investigate the causal relationship between sarcopenia-related traits and inflammatory bowel disease and its subtypes on each other. The inverse-variance weighted method was used as the primary analysis method to assess the causality, and a comprehensive sensitivity test was conducted. Genetically predicted appendicular lean mass was significantly associated with inflammatory bowel disease (OR = 0.916, 95%CI: 0.853-0.984, P = 0.017), ulcerative colitis (OR =0.888, 95%CI: 0.813-0.971, P = 0.009), and Crohn's disease (OR = 0.905, 95%CI: 0.820-0.999, P = 0.049). Similar results also revealed that the usual walking pace was causally associated with Crohn's disease (OR = 0.467, 95%CI: 0.239-0.914, P = 0.026). Reverse mendelian randomization analysis results found that genetic susceptibility to inflammatory bowel disease, and Crohn's disease were associated with lower appendicular lean mass. A series of sensitivity analyses ensured the reliability of the present research results. The mendelian randomization study supports a bidirectional causality between inflammatory bowel disease, Crohn's disease and appendicular lean mass, but no such bidirectional causal relationship was found in ulcerative colitis. In addition, genetically predicted usual walking pace may reduce the risk of Crohn's disease. These findings have clinical implications for sarcopenia and inflammatory bowel disease management.

Abstract 16629: Comparison of Clinical and Genetic Risk Model for Ischemic Stroke After Atrial Fibrillation Catheter Ablation

Introduction: CHA 2 DS 2 -VASc score (CVS) is used to estimate risk of stroke in atrial fibrillation (AF) patients. But, CVS does not include genetic risk. We explored clinical and genetic risks for ischemic stroke (IS) after AF catheter ablation (AFCA). Methods: We used genome-wide association study (GWAS) data in European (34217 IS, 406111 controls) and Asian (22664 IS, 152022 controls) to develop polygenic risk score (PRS) for IS in 2897 independent Korean AF patients (Median 60 years, male 74.0%, paroxysmal AF 66.3%, anticoagulation rate 60% in 1367 patients with CVS ≥ 2 who underwent AFCA. Patients with IS within 2 weeks after AFCA were excluded. In the independent AF cohort during median 50 [IQR 28-94] months follow-up, 48 experienced IS after AFCA. We developed two different CVS-combined PRS models in the independent cohort using European and Asian GWAS data. Using p-value &lt;5e-8, rs635634 and rs671 were used in CVS-combined European PRS (CVS-EPRS) and CVS-combined Asian PRS (CVS-APRS) model, respectively in the independent cohort. We compared C index of risk models to investigate prediction power for IS. Results: CVS was higher in patients with IS than in their counterparts (3.0 IQR [1.0, 4.0] vs. 1.0 [1.0, 2.0], p&lt;0.001). Overall C index was 0.716 in CVS model, 0.711 in CVS-EPRS model, and 0.725 CVS-APRS model. For 1-year IS after AFCA, CVS-APRS model improved C index as compared to CVS model (0.834 vs. 0.813, p=0.037). For 3-year IS after AFCA, C index was higher in CVS-APRS model rather than CVS-EPRS model (0.746 vs. 0.721, p=0.030). In patients with CVS &lt; 2, both CVS-APRS (0.849, p=0.013) and CVS-EPRS (0.766, p=0.027) models showed better prediction for 1-year IS compared to CVS model (0.523). Conclusions: In AF patients with AFCA, genetic polymorphism with clinical risk factors contributed to predict 1-year IS. Genetic contribution was more obvious in AF patients with CVS &lt;2. However, ethnicity might be an important factor in adapting genetic contributions to predicting IS.

The effect of immunomodulatory drugs on aortic stenosis: a Mendelian randomisation analysis.

There are currently no approved pharmacological treatment options for aortic stenosis (AS), and there are limited identified drug targets for this chronic condition. It remains unclear whether inflammation plays a role in AS pathogenesis and whether immunomodulation could become a therapeutic target. We evaluated the potentially causal association between inflammation and AS by investigating the genetically proxied effects of tocilizumab (IL6 receptor, IL6R, inhibitor), canakinumab (IL1β inhibitor) and colchicine (β-tubulin inhibitor) through a Mendelian randomisation (MR) approach. Genetic proxies for these drugs were identified as single nucleotide polymorphisms (SNPs) in the gene, enhancer or promoter regions of IL6R, IL1β or β-tubulin gene isoforms, respectively, that were significantly associated with serum C-reactive protein (CRP) in a large European genome-wide association study (GWAS; 575,531 participants). These were paired with summary statistics from a large GWAS of AS in European patients (653,867 participants) to then perform primary inverse-variance weighted random effect and sensitivity MR analyses for each exposure. This analysis showed that genetically proxied tocilizumab was associated with reduced risk of AS (OR 0.56, 95% CI 0.45-0.70 per unit decrease in genetically predicted log-transformed CRP). Genetically proxied canakinumab was not associated with risk of AS (OR 0.80, 95% CI 0.51-1.26), and only one suitable SNP was identified to proxy the effect of colchicine (OR 34.37, 95% CI 1.99-592.89). The finding that genetically proxied tocilizumab was associated with reduced risk of AS is concordant with an inflammatory hypothesis of AS pathogenesis. Inhibition of IL6R may be a promising therapeutic target for AS management.

ASSESSING THE CAUSAL RELATIONSHIP BETWEEN SEPSIS AND AUTOIMMUNE: A MENDELIAN RANDOMIZATION STUDY.

Objective : Numerous epidemiological studies have identified a potential link between sepsis and a variety of autoimmune disorders. The primary objective of this study is to delve deeper into this connection, investigating the potential causal relationship between sepsis and autoimmune disorders through the application of Mendelian randomization (MR). Methods : To assess the potential genetic impact on sepsis risk relating to susceptibility toward immune-related outcomes, we used summary data from the largest European genome-wide association studies (GWAS) on these conditions using a two-sample MR framework. Single nucleotide polymorphisms-which had strong associations with the nine traits-were extracted from the GWAS and examined their effects in an extensive European sepsis GWAS (486,484 cases and 474,841 controls). We used inverse-variance weighted MR, weighted median, and MR Egger for analyses, supplementing these with sensitivity analyses and assessing level pleiotropy using MR methodologies. We also executed a reverse MR analysis to test sepsis' causal effects on the designated autoimmune traits. Results : With primary sclerosing cholangitis being the exception, our MR analysis suggests that susceptibility toward most autoimmune diseases does not affect sepsis risks. The reverse MR analysis did not validate any influence of sepsis susceptibility over other autoimmune diseases. Our primary inverse-variance weighted MR analysis outcomes found general confirmation through our sensitivity MR examinations. Variance in the exposures, as dictated by the single nucleotide polymorphism sets used as MR instruments, ranged between 4.88 × 10 -5 to 0.005. Conclusion : Our MR research, centered on a European population, does not validate a correlation between susceptibility to the majority of autoimmune disorders and sepsis risk. Associations discerned in epidemiological studies may owe partly to shared biological or environmental confounders. The risk susceptibility for primary sclerosing cholangitis does relate to sepsis risk, opening doors for personalized precision treatments in the future.