The important role of genetics in heart disease

The important role of genetics in heart disease
Heart disease is the leading cause of death in America and often runs in families. Coronary heart disease involves the buildup of plaque in the blood vessels, which can cut off oxygen supply and nutrients to the heart. Whether you have a family member who had a heart attack or you’re curious about what the latest science has to offer, let’s understand what’s currently possible to detect through genetic testing. 
Written by Christina Ren, Certified Genetic Counselor 
Orchid offers advanced genetic testing for couples who want their child to have the best shot of a healthy life. “Genetics for Humans” is where we unpack how genetics impacts our everyday lives and the latest tools to help you build a healthier family.  

Despite medical advancements, heart disease remains the leading global cause of death, accounting for about a quarter of all deaths in the United States. The impact of this common disease is staggering: each year, more than 900,000 individuals in the United States have a heart attack or die of heart disease. How can you better predict your chance of developing heart disease through genetic testing? 

Does heart disease run in families? 

If your mom or dad had a heart attack, you might wonder if that’s going to happen to you or your children, too. 

It turns out coronary artery disease (CAD) has important genetic underpinnings — family and twin studies estimate that CAD is about 40 to 60% heritable. These genetic influences on heart disease tend to have a greater impact on early-onset heart disease (before age 60). Studies have also shown that family history is a risk factor independent of clinical risk factors such as obesity, physical inactivity, high blood pressure, and diabetes.

What all this means is that we tend to see heart disease cluster in families. Familial clustering happens more often when events like heart attacks happen to someone at a younger age. First-degree relatives (children, full siblings) of an individual with early-onset coronary heart disease have at least double the risk of developing it, too, compared to the general population.

Is there a single genetic cause for heart disease?

The short answer is no — there isn’t a specific “Heart Disease Gene” like the Huntington’s disease gene that explains it all. 

The one exception is a rare disorder called familial hypercholesterolemia (FH). For individuals with FH, they have a genetic mutation in a single gene that causes them to have very high cholesterol levels and therefore have up to a 3-fold increased risk for coronary heart disease. This information can be very valuable for FH carriers and their families. 

But familial hypercholesterolemia is rare. Only 0.4% of the general population have an FH mutation. This means the vast majority of people that have heart disease don’t have an FH mutation. So, if you just did genetic testing looking for an FH mutation, most of the time, you wouldn’t find anything meaningful to you.

Given that familial hypercholesterolemia only explains a very small portion of heart disease cases, what about most cases of CAD? After decades of research, what’s become increasingly apparent is that most of the time, there is no single genetic cause of heart disease. The reality is more complex. To properly measure genetic predisposition to heart disease, you have to assess the whole landscape by looking at many genes and genetic markers combined.  

Is there a genetic test for heart disease?

Yes, there is now a way to measure your genetic predisposition to heart disease. This is different from a diagnosis, however. Genetic screening can tell you if you are more or less likely to develop heart disease than the average person based on your genetic background. 

This is done by comparing the genetic makeup of tens of thousands of individuals diagnosed with coronary artery disease (“cases”) with individuals without CAD (“controls”). A recent study with data from over 400,000 individuals suggests that based on genetics, 8% of the general population have over a 3-fold increased risk for CAD — the same disease risk predicted if you were to have a rare single gene mutation for familial hypercholesterolemia. 

What’s more, these genetic risk scores identified more individuals with increased risk of heart disease previously missed by conventional risk factors like family history, high cholesterol, or hypertension alone. This means that a doctor during a routine appointment would not have identified these individuals with an increased genetic predisposition to heart disease. 

With advanced genetic testing like what we do here at Orchid, you can get a sense of your genetic predisposition to heart disease and remove some of the guesswork on what you can pass on to your future children. 

What actions can I take based on the information from a genetic test for heart disease?

If you or your future child has an elevated genetic risk for heart disease, the risk of developing heart disease at some point in life can be up to 3 times higher than in the general population. 

The useful thing about your results is that if you identify certain genetic vulnerabilities that can impact you or your future children, you can potentially do something about it and mitigate these risks. Ways you can act on your results include:

  • Offset genetic risks with healthy lifestyle choices. Genetics is just one component of your chances of getting heart disease. This means you can significantly lower your overall risk with personal lifestyle choices, which is especially important if you have a higher genetic risk. Known as Life’s Simple 7, here are seven key factors that contribute to heart health. These are probably things you’ve heard over and over again, but there’s a reason why: people with at least five of these factors have a 78% reduced risk for heart-related death compared to people without any healthy lifestyle factors. 
  • Consider talking to your doctor about taking medications like statins. Research has found that people with the highest genetic risk scores seemed to benefit the most from taking statins, which is a medication used to lower cholesterol. Every 40 mg/dL drop in cholesterol levels reduces the risk of heart attack by 24% on average, and 44% for people with high genetic risk. 
  • Embryo screening to reduce your child’s potential genetic risks. Embryo screening allows you to quantify each embryo’s genetic risk for heart disease and other common conditions. This allows you to prioritize the transfer of embryos with the lowest genetic risk and thus reduce your future child’s genetic risks.  

Key takeaways 

  • Heart disease is a very common condition that is the leading global cause of death despite medical advancements in treatment and prevention. 
  • Past family studies have shown that genetics play an important role in the chance of developing heart disease.
  • Advanced genetic testing can now see if this genetic component to heart disease can be quantified for you and your family. 
Resources 

Orchid offers advanced genetic testing for couples planning on building their family. We use advanced tools and smart, caring humans to help you give your future children the best shot of a healthy life. Conceive with greater confidence and peace of mind


12/21/2020
Genetics
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