The Future of Heart Disease Treatment Determined by Genetics

Heart disease is the most common cause of death not only in Phoenix, but across the world, killing 17 million people each year. This century, the reality of eliminating this global pandemic is more likely than ever, and it all resides in our genes.

Robert Roberts, MD, a professor at the University of Arizona College of Medicine – Phoenix and chair of the International Society of Cardiovascular Translational Research, along with Stanford University School of Medicine Assistant Professor Themistocles Assimes, MD, PhD, were recently published in the Journal of the American College of Cardiology (JACC) for their research on the prevention and management of Coronary Artery Disease using genetic risk variants.

“This research can transform the management of Coronary Artery Disease,” Dr. Roberts said. “In the next few years, we will be treating people asymptomatic who have genetic risks. It’s a golden opportunity.”

Dr. Roberts said the UA College of Medicine – Phoenix, in collaboration with the Translational Genomics Research Institute(TGen), hopes to give Phoenix a leading role in being among the first to introduce a new preventive approach to tackle heart disease.

There is substantial evidence that heart disease is preventable when a person changes their lifestyle by decreasing conventional risk factors such as smoking, high blood pressure, increased cholesterol, diabetes and, to some extent, obesity. Those changes are associated with a 30 to 40 percent reduction in cardiac death and cardiac events such as heart attacks, according to Dr. Roberts. In the 1950s, epidemiologists discovered that about 50 percent of the risk of Coronary Artery Disease is encoded in a person’s genes.

Dr. Roberts’ team and a group in Iceland independently identified the first gene related to Coronary Artery Disease, 9P21, in 2007.

“Once we identified 9P21, we were impressed by the fact that its risk was independent from any of those conventional risk factors,” Dr. Roberts said. “This had big implications for us because many people postulated that this would be the last century for heart disease and certainly, whether that is true or not, it is highly likely that at the turn of this century, heart disease will be very minimal.”

After discovering 9P21, it was decided that in order to find those genetic risks, researchers should pool their efforts and resources. In a sample size of over 200,000 cases and controls, the genome of each individual in the sample was analyzed using 11 million DNA markers. Dr. Roberts’ team at the University of Ottawa Heart Institute joined with Harvard University, the University of Pennsylvania, the University of Oxford, University of Cambridge, Wellcome Trust Group at the University of Leicester, the University of Munich and the deCODE Icelandic group in the largest collaboration in cardiology in history. It resulted in identifying 60 genetic variants that are associated with an increased risk of Coronary Artery Disease.

“Let’s suppose I see a female between the ages of 40 to 60 who has an LDL cholesterol of 175 mg/dL with no other risk factors. According to current cardiology guidelines, you must have two or more risk factors to start receiving treatment. We would say, ‘Come back to see me and if you develop other risk factors, we will treat you,’” Dr. Roberts said. “Genetic testing will tell us if you are at risk and if you are at risk, you’d then have two risk factors, and we can start treatment immediately. Using genetic variants, we can predict if you are at risk and also your response to statin therapy, the number one drug to prevent heart disease by lowering your cholesterol.”

Testing to determine a person’s genetic risk is done by analyzing DNA from a sample of blood or saliva using modern chip technology. Unfortunately, as this is new and only recently has shown that genetics predict the risk of heart disease, health insurance companies do not reimburse for genetic testing for heart attacks.

“These genetic risk variants are very common,” Dr. Roberts said. “The risk for heart disease depends on how many genetic variants one has rather than their intensity. Genetic risk is unique in that it can be determined at birth or anytime later, since your DNA does not change in one’s lifetime.”

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Teresa Joseph
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