[Genetic analyses as basis for a personalized medicine in patients with coronary artery disease]

Knowledge about the etiology of coronary artery disease (CAD) entered new dimensions using genome-wide association studies. The current situation is that 46 chromosomal loci have been identified to be associated with CAD with genome-wide significance, i.e. p<5×10(-8), in Western Europeans. As the individual DNA sequence remains unchanged after fertilization, the risk variants cannot occur due to confounders, such as secondary disease processes. Thus, it can be proposed that these variants are directly affecting a primary and thereby causal pathophysiological process in CAD. Interestingly, only 20% of the effects mediated by the identified loci can be explained by the influence of traditional risk factors. This implies that yet unknown mechanisms and, as a consequence, new therapeutic targets play an important role in the pathophysiology of CAD. However, the high allele frequency of risk loci was also surprising. In the diploid chromosome set Western European individuals carry on average 30-50 risk variants at the 46 loci. Considering this, every individual in the population carries a larger or smaller genetic predisposition for CAD. On the other hand it is remarkable that many risk allele carriers seem to be able to compensate the genetic risk: even in old age not everyone suffers from CAD. This indicates yet unknown gene-gene and gene-environment interactions and limits the current possibilities in individual risk prediction.