Plain language summary
Aortic stenosis (AS) is a form of heart disease that is an abnormal narrowing of the aortic valve in the heart, which restricts blood flow. Although being over the age of 75 appears to increase the risk for development, it is unclear as to who else may be at risk. A better understanding of genetic factors, which may be involved in its development could better help to identify those at risk. This meta-analysis of 10 cohort studies aimed to determine genetic contributors to AS and possible mechanisms involved. The results showed that 15 different gene variations were strongly associated with AS including those in the CELSR2-SORT1, NLRP6, LPA and SMC2 genes. Interestingly some of these genes were also identified in individuals with African and Latin American ancestry. It was concluded that these genes, many of which are associated with hardening of the arteries, altered lipid metabolism, excess storage of fat, and inflammation may all contribute to AS. This study could be used by healthcare professionals to understand that there are specific genetic contributors to the development of AS and that in the future we may be able to target these to identify high-risk individuals and use them in therapeutic management.
Abstract
AIMS: Although highly heritable, the genetic etiology of calcific aortic stenosis (AS) remains incompletely understood. The aim of this study was to discover novel genetic contributors to AS and to integrate functional, expression, and cross-phenotype data to identify mechanisms of AS. METHODS AND RESULTS A genome-wide meta-analysis of 11.6 million variants in 10 cohorts involving 653 867 European ancestry participants (13 765 cases) was performed. Seventeen loci were associated with AS at P ≤ 5 × 10-8, of which 15 replicated in an independent cohort of 90 828 participants (7111 cases), including CELSR2-SORT1, NLRP6, and SMC2. A genetic risk score comprised of the index variants was associated with AS [odds ratio (OR) per standard deviation, 1.31; 95% confidence interval (CI), 1.26-1.35; P = 2.7 × 10-51] and aortic valve calcium (OR per standard deviation, 1.22; 95% CI, 1.08-1.37; P = 1.4 × 10-3), after adjustment for known risk factors. A phenome-wide association study indicated multiple associations with coronary artery disease, apolipoprotein B, and triglycerides. Mendelian randomization supported a causal role for apolipoprotein B-containing lipoprotein particles in AS (OR per g/L of apolipoprotein B, 3.85; 95% CI, 2.90-5.12; P = 2.1 × 10-20) and replicated previous findings of causality for lipoprotein(a) (OR per natural logarithm, 1.20; 95% CI, 1.17-1.23; P = 4.8 × 10-73) and body mass index (OR per kg/m2, 1.07; 95% CI, 1.05-1.9; P = 1.9 × 10-12). Colocalization analyses using the GTEx database identified a role for differential expression of the genes LPA, SORT1, ACTR2, NOTCH4, IL6R, and FADS. CONCLUSION Dyslipidemia, inflammation, calcification, and adiposity play important roles in the etiology of AS, implicating novel treatments and prevention strategies.
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