The Genetic Risk of Heart Disease
The sequencing of the human genome gave researchers hope that genetic knowledge could be used to dramatically reduce mortality from a host of diseases afflicting society. By studying the differences in DNA sequences that drive genetic variation in humans, scientists hoped to find genetic links to diseases, understand the mechanisms underlying the disease process, and develop treatments that target these mechanisms. Though there has been some success with identifying genetic mutations that carry high risk of disease, including mutations found to cause sickle cell disease and Huntington’s disease, it has become increasingly clear that many diseases, including cardiovascular disease, can be caused by a number of genetic variants that are relatively common in the human population. This makes it difficult to pinpoint which genetic variant can be targeted for effective drug development. However, as described in an editorial published in Circulation, progress has recently been made in using knowledge of common genetic variations to predict the risk of heart disease in individuals and to manage their treatment.
Scientists have found that the more genetic variants an individual has that is associated with heart disease, the more likely disease is to occur. Identifying the presence of these variants can improve the prediction of future heart disease beyond that which is provided by traditional risk factors such as high blood pressure, obesity, and smoking. Admittedly, though, the additional predictive ability is modest. Further, researchers do not understand how many of the genetic variants functionally lead to increased heart disease, confounding efforts to develop treatments.
Despite these shortcomings, one study, the Myocardial Infarction Genes (MI-GENES) Clinical Trial, found that receiving genetic counseling could alter patient treatment behavior. Study participants counseled of their risk for heart disease based on both their genetic and traditional risk factor profile were more likely to take cholesterol-lowering drugs than a group randomized to receive only the traditional risk factor-based heart disease prediction.
This study gives a glimpse into how genetic knowledge of heart disease may be used in clinical practice to improve patient outcomes. As the authors describe, though, there is much more work to be done. Researchers must find a way to effectively incorporate the constantly evolving understanding of genetics into their risk prediction scores, and they must determine how to optimally interpret and communicate complex genetic results to providers and patients. Nevertheless, this research brings science one step closer to effectively using genetics to treat a disease affecting millions of people globally.