The interplay of genetics and modifiable risk in atherosclerosis

Abstract Genetic disposition accounts for about half of the risk to develop coronary artery disease (CAD). Yet, Mendel's Laws fail to explain its high prevalence. The conceptual dilemma was resolved by the common-disease—common-variant hypothesis, which proposes that common diseases like CAD are caused by multiple common genetic variants. Mapping of the human genome and consecutive genomewide association studies verified this hypothesis showing that hundreds of risk alleles contribute to the development of atherosclerosis. Many of these risk alleles are found with a high frequency in our population. Thus, all of us carry such risk alleles in high numbers and cumulatively they provide the knitting pattern for atherosclerosis to develop so often. The effects of individual risk alleles are small yet multiplicative, such that disease prevalence increases logarithmically the more risk alleles a person carries. Importantly, classical risk factors integrate their detrimental effects into the same logarithmic function, which explains the seeming aenigma that people with the strongest genetic disposition have the largest benefit from treatment of modifiable risk factors. It seems fruitful, therefore, to analyse inherited and exogenous factors contributing to CAD jointly: 1.) to uncover novel pathogenetic mechanisms, 2.) to identify new treatment targets, and 3.) to personalize medical care. Being part of this journey for 30 years, I want to report some moments when I got excited about these discoveries. For example, association of the 9p21 locus with CAD being a proven fact after many years of frustration, mendelian randomization studies separating delinquents from bystanders in the aetiology, new biology coming into play, and finally the paradox that genetics do most harm in people with modifiable risk factors. (Graphical Abstract).