Editor’s note: To mark this month devoted to the heart, cardiology experts at Penn Medicine are writing a guest column each week in February exploring a different aspect of cardiovascular health.
You already knew that lifestyle choices — what you eat, how much you exercise, whether you smoke — play a big role in determining your risk of coronary heart disease, the most common type of heart disease and the one that causes heart attacks. But did you know that your genes also contribute to your risk? In fact, your genes are no less important, and no more important, than lifestyle. Heart disease is driven half by the choices you make and half by what you inherited from your parents.
In the last decade, we’ve learned a lot about how your genes influence heart disease. Hundreds of genes across all the chromosomes make small contributions that either increase or decrease your risk. You can think of each of these genes as having a good version or a bad version, and you might have either version of any given gene. For most people, it’s a wash — some genes are good versions, other genes are bad versions, and they balance out.
But some people are unlucky and have mostly bad versions of genes — or in rare cases one very, very bad gene — which means they’re born with high genetic risk of getting heart disease. For example, a person might inherit a sky-high cholesterol level. Fortunately, when it comes to heart disease, genes aren’t destiny; they’re only part of the picture. What we’ve learned in the last few years is that if you were born with high genetic risk, you can still do something about it. Good lifestyle choices will cancel out the effects of bad genes, and your risk will be similar to an average person’s risk. Your doctor might advise you to do other things to address your high genetic risk, such as taking a cholesterol-lowering medication.
It cuts both ways. Some people are genetically protected against heart disease. But that’s not license to live a hedonistic lifestyle. Poor choices, especially the choice to smoke, will cancel out or even outweigh the effects of good genes. Good choices will make an already low risk of heart disease even lower.
The bottom line is that, yes, you can put part of the blame (or gratitude) on your parents. But you’re just as responsible for your health. Good lifestyle choices will help you no matter what genes you have. Don’t smoke. Eat healthy foods in moderation. Exercise regularly. Try to maintain an ideal body weight.
Still, researchers such as ourselves are working hard to help people who have high genetic risk through no fault of their own. To do this, we’re seeking out those rare people who have one very, very good gene and are practically immune to heart disease. We’ve been able to identify some of these “genetic superheroes” and figure out the special gene that’s protecting them. Now that we’ve identified that special gene, can we use it to help people who didn’t win the genetic lottery?
All people’s genes are the same on the day they are born as on the day they die. But a new technology known as gene editing is now making it possible to tweak a person’s genes midway through life.
What if we could identify people who were born with high genetic risk, and use onetime gene editing to put in the special protective gene and rebalance the odds back in their favor? What if we could use gene editing as a “vaccination” that could reduce an entire population’s risk of heart disease, especially in poor countries where heart disease is rapidly becoming the leading cause of death?
We’re working hard to make this a reality. Studies in mice look promising, and a gene-editing therapy to reduce heart disease risk may be ready for clinical trials in the next five to 10 years. The day may come, not too far in the future, when all young people will undergo gene sequencing to determine their inborn risk of heart disease. Those with high genetic risk will have the choice to receive a “vaccination” that will permanently mitigate that risk. Good lifestyle choices will still be important, no matter who you are. We’ll have reached a time when your heart health will truly be entirely in your own hands.