Personalized Medicine for Heart Disease

Gene tests may help doctors identify people at risk of heart disease early and tailor treatment for several other illnesses. Here’s what you should know.  

Heart disease is the leading cause of death in the United States for both men and women. It doesn’t discriminate. It claims more lives than all forms of cancer combined. The good news is that scientists now have information about genes to tailor treatment and for prevention.

The Human Genome Project generated the first sequence of the human genome, the human blueprint, 20 years ago. That information, many hope, will pave the way for changes in medical practice.

Researchers have identified more than 40 variant genes that increase the risk of sickness or death from sudden cardiac death, heart failure, and other types of cardiovascular disease, according to the American College of Medical Genetics and Genomics.

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For example, genetic variants may cause the heart to reset more slowly than normal after each contraction, which may cause electrical instability of the heart and may lead to fainting, arrhythmias, or even sudden death. 

You’re not doomed if you inherit a dangerous gene, and the information could be useful.

"With most genetic cardiovascular diseases, inheriting a mutation (or variant) from a parent substantially increases the risk of getting the disease but does not guarantee the disease," Kiran Musunuru, MD, PhD, a cardiologist and genetics researcher at the University of Pennsylvania, said. "In some cases, it might be possible to act early and prevent the disease. In other cases, having the mutation for a genetically caused cardiovascular condition might lead to different and possibly more aggressive treatment."

Gene-linked cardiovascular conditions include:

• Cardiomyopathies, heart muscle diseases that can lead to heart failure
• Thoracic aortic aneurysms and dissections, which can cause your body's major artery to balloon and rupture
• Arrhythmias, abnormal heart rhythms that can be deadly
• Familial hypercholesterolemia, extremely high LDL cholesterol levels that greatly increase the risk of heart attacks

Other risk factors for heart problems include:

• High blood pressure
• Diabetes
• Kidney disease
• Smoking
• Nutrition
• Obesity
• Family history

It’s possible that one day correcting faulty genes will treat heart disease. In the meantime, genetic information can help doctors tailor treatment to a patient, moving towards what’s called personalized or precision medicine.

The result may be more precise dosing that would reduce side effects, streamline drug testing, and lower costs. People at risk could learn the news in time to make important changes in diet or exercise.

In one study, researchers at the University of Virginia discovered a genetic variant tied to an increased risk for stroke, while uncovering new details about an important metabolic pathway that may reveal clues about treatment.

Specifically, the researchers found a protein coding gene called GNMT, or Glycine N-Methyltransferase. It converts methionine to homocysteine (both are amino acids). Elevated levels of homocysteine can cause heart attacks, strokes, and blood clots.

“As genome sequencing becomes more widespread, clinicians may be able to determine if a person's risk for abnormally high levels of homocysteine is elevated,” noted lead researcher Stephen R. Williams, PhD, a staff scientist in Computational Biology at 10X Genomics, a research organization.

That might lead to earlier changes in diet.

While scientists are studying personalized medicine in relation to heart disease, doctors are emphasizing that patients focus on prevention — exercising, eating a well-balanced diet that is low in cholesterol, and quitting smoking.

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