The Role of Genetic Risk Factors in Predicting CAD
The 33 genetic risk variants for coronary artery disease (CAD) are less potent predictors of CAD when compared to biomarkers. Further, routine genetic screening is unlikely until management is improved with genetic testing, according to a state-of-the-art paper published on Oct. 3 in the Journal of the American College of Cardiology.
According to the study, over 1,319 genetic variants have been identified to be associated with increased risk for 160 diseases. The genome-wide association studies (GWAS) found 33 genetic variants for CAD. Of the 33 variants, the increased risk varies from 6 percent to 92 percent with a mean increased risk of 18 percent occurring on average in 47 percent of the population. In the CARDIoGRAM study of 23 variants, the average per individual was 17, the minimum 7, and the maximum 37. The top 10th percentile has an odds ratio of 1.88 and the lowest percentile an odds ratio of 0.55.
In addition, eight of the variants mediate their risk through lipids and another two through hypertension, with 23 loci acting independently of known risk factors. Further, most genetic risk variants exhibit higher risk in individuals with early onset than for those with late onset CAD, and most are located in DNA sequences that do not code for protein, note Robert Roberts, MD, MACC, and Alexandre F. R. Stewart, PhD, of the John & Jennifer Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute, Ottawa, Ontario, Canada, and authors of the study.
The authors add that the major barrier to genetic testing for CAD is that no specific treatment exists as of yet, and conclude that until the mechanisms are discovered and management is improved, genetic testing is unlikely to become routine. "The discovery of 33 genetic risk variants for CAD and the increased awareness of prevention will no doubt catalyze the search for improved treatments and the elucidation of their biology and pathophysiology," they add.
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