Is Hypertrophic Cardiomyopathy Genetic?

Hypertrophic cardiomyopathy (HCM) affects about 1 in 250 to 500 people in the U.S.

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

And many people may not realize they have HCM — a type of heart disease that thickens your heart muscle.

If you’ve been recently diagnosed with HCM, you may be full of questions. One question might be: Is hypertrophic cardiomyopathy genetic?

Does hypertrophic cardiomyopathy run in families?

HCM is primarily a genetic condition. Known genetic mutations (gene changes) are identified in about 60% of HCM cases, says cardiologist Maran Thamilarasan, MD.

If one parent has one of the hypertrophic cardiomyopathy genes, each child has a 50% chance of inheriting it. And both types of HCM — obstructive (blocks blood flow) and nonobstructive (doesn’t block blood flow) — can be inherited.

And while we know there’s a connection between your genes and HCM, there’s still more that researchers need to learn about familial HCM. For example, researchers continue to discover additional genes that may be responsible for HCM.

“We also don’t know yet what may cause a gene to ‘turn on,’” explains Dr. Thamilarasan. “We don’t really know what percentage of people with these altered genes will develop HCM. One study suggests that about 16% of people who are gene-positive developed phenotypic evidence (traits or characteristics that can be measured) for the disease over the course of a seven-year follow-up.”

Should your family get genetic testing?

If you have HCM, your close family members — parents, siblings and children — should consider genetic testing.

“Often, we don’t make a diagnosis early enough,” says Dr. Thamilarasan. “Some people with the condition are at higher risk for cardiac events, and we need to know about it.”

During a genetic test, a sample of your blood or saliva is used to look for changes in your genes. In addition to genetic testing, your healthcare provider may use other screening tests, like an exercise stress echo test, cardiac event monitor and cardiac MRI, to diagnose HCM.

Another reason why genetic testing is so vital? Other diseases can have similar symptoms, notes Dr. Thamilarasan.

Symptoms like chest pain and palpitations, dizziness, shortness of breath, fatigue and edema (swelling) can lead doctors down other potential paths like coronary artery disease (CAD), pulmonary disease or even allergies.

Genetic testing can also identify other medical conditions that may cause thicker heart muscles, known as HCM “phencopies,” reports Dr. Thamilarasan.

“Hypertension can mimic HCM. Cardiac amyloidosis or Fabry disease can also give the same clinical picture. If these other diseases are present, it might require a different treatment pathway,” he continues. “We want to assess for these.”

What to do if you’re high risk

While HCM is a lifelong condition, there are steps you can take to protect your heart and prevent complications like atrial fibrillation (AFib), congestive heart failure or sudden cardiac arrest.

It’s also important to understand how HCM can affect your heart. The genes that may cause HCM are ones that are responsible for the structure of the heart muscle. While HCM can impact any part of your heart’s muscle, it traditionally affects the septum (the middle wall). This can lead to outflow tract obstruction (or blockage). But thickness in other locations can lead to symptoms, both from stiffness in your heart, as well as restricting the amount of space your heart’s left ventricle has to pump blood.

Depending on your risk and symptoms, your healthcare provider may recommend following a heart-healthy lifestyle, which includes eating heart-healthy foods, focusing on quality sleep and engaging in regular physical activity.

They may also recommend medications like:

Beta-blockers
Calcium channel blockers
Diuretics
Myosin inhibitors

In some situations, surgery may be required. Options could include a septal myectomy, alcohol septal ablation or an implantable cardioverter defibrillator (ICD).

Key takeaways

Not all people with altered HCM genes will develop the heart condition. And while it can be scary to hear that you may have inherited genes that can cause a heart condition, genetic testing can play a big role in diagnosing and understanding your HCM.

“Identifying the condition early and assessing for the presence of HCM genes is important so we can monitor and treat appropriately,” says Dr. Thamilarasan.