Abstract
Polygenic risk scores (PRSs) capture the polygenic architecture of common diseases by aggregating genome-wide genetic variation into a single score that reflects individual’s disease risk, affording a new opportunity to identify downstream molecular pathways involved in disease pathogenesis. We performed an integrative analysis to characterise associations of PRSs of five cardiometabolic diseases with 3,442 plasma proteins in 3,175 healthy individuals. Through polygenic association scans we identified 48 plasma proteins whose levels were associated with PRSs for coronary artery disease (CAD), chronic kidney disease (CKD), or type 2 diabetes (T2D). This approach identified both well-known disease-associated proteins as well as those with previously no known link to these diseases. We found that PRSs to protein associations were largely truly polygenic; independent of single loci and genomic regions expected to have strong effects on protein levels. Our integrative analysis and laboratory experiments revealed a role for polygenic effects on several well-known disease proteins and identified several promising novel targets for follow-up studies, including genes which through Mendelian randomization analysis displayed causal evidence for effects on disease risk. Mouse studies highlighted specific tissues and phenotypes for PRS-associated human proteins. We found that implicated genes were responsive to dietary intervention in mice and showed strong evidence of druggability in humans, consistent with PRS-associated proteins having therapeutic potential. Overall, our study provides a framework for polygenic association studies, and demonstrates the power of polygenic scores to unravel novel disease biology.