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How Genetics Impacts Heart Health: American Heart Month

Stephanie E. Wallace

Last week, we shared that 1 in 200 people have a heart condition with a genetic basis and most people with inherited heart conditions often do not experience symptoms or know they are at risk. As a part of Color’s clinical grade services, we test 30 genes for mutations related to four types of inherited heart conditions: arrhythmias, familial hypercholesterolemia, cardiomyopathies, and arteriopathies. Today, our Lead Cardiovascular Genetic Counselor, Stephanie Wallace, MS, LCGC, is talking about what to do with genetic testing results that show a positive result for a mutation related to cardiovascular risk.

One of the most common questions I hear from people looking to be proactive about their health is, “I have a family history of heart disease — does that mean I’m at risk too?” Family history can be a strong indicator for your risks, whether they are present in your DNA or because we tend to share a similar environment with family members. What can your family history really tell you about your risk and what information is the most helpful?

First, it’s important to understand the difference between inherited and familial health conditions. There are some heart conditions that can be passed from parent to child because of one small change in the DNA–these are inherited and include conditions like hypertrophic cardiomyopathies, Long QT Syndrome, Marfan Syndrome and familial hypercholesterolemia. We have over 20,000 genes in our body and inherited heart conditions are caused by approximately 50–100 genes.

When we think of familial conditions, we think of our genes and our environment. Most heart diseases — like high cholesterol, high blood pressure, diabetes, and atrial fibrillation — aren’t due to single changes in DNA. They may be due to a combination of thousands of genetic changes, environment, and lifestyle choices. Another way to imagine your overall risk is like a jar of marbles–as the jar of marbles gets more full, your overall risk for a cardiovascular condition increases.

Genetics form the foundation of the marble jar. Think of genetic factors as the marbles at the bottom of a jar. They are the marbles you are born with, and they remain unchanged throughout your life, despite diet or lifestyle changes. These marbles can be large or small depending on how much they each influence risk.

Lifestyle choices can increase or decrease the number of marbles. Unhealthy habits like smoking or lack of physical activity can increase the number of marbles in your jar, which means your risk increases. As you improve these habits, the number of lifestyle marbles in your jar decreases, which decreases your overall risk.

A full marble jar means coronary heart disease has developed. When the number of marbles in the jar reaches the top, that means your risk is high enough that you develop coronary heart disease. Individuals who start with more genetic marbles in their jar are closer to filling it, which is why their overall risk is increased.

If you have a family history, making your provider aware of that history is very important, so that they can determine how you should be treated. Keep in mind that family history changes over time, so updating that family history is equally important. When sharing your history with your provider, be sure to include:

– Type of disease: Heart disease can mean many different things, from a blockage in the artery to an arrhythmia that causes the heart to stop. Ask your family for details — they may not know the diagnosis but your provider may be able to determine if additional screening is needed based on information like if they had surgery and the specific circumstances around the death of relatives. All of this information can help to determine what risks your family history may suggest.

– Age: Knowing what age a person develops disease is very important for two reasons: (1) it can influence when to start screening other members of the family and (2) disease at an early age can be a red flag that there is an additional genetic component. Risk for heart disease goes up with age, but when we see heart disease in a younger individual — like a heart attack at age 35 — we know that there may be a higher chance for an inherited form of heart disease.

For more information on risk factors, family history and heart disease visit the American Heart Association