Sabrina Cuddy • March 21, 2024
April’s Topic is Genetic Testing

Who should have genetic testing, why, and when?

Suppose you have been clinically (through an EKG, echocardiogram, and a visit with a cardiologist) diagnosed with HCM. In that case, most experts recommend that you have genetic testing to determine the underlying reason your heart is too thick.

Why does it matter?   

Some hearts look like HCM but have a specific genetic mutation for one of the HCM spectrum disorders – Amyloidosis, Fabrys, Danon, Sarcoidosis, etc. These disorders are often managed differently from HCM alone, so you need to know if you have one.

HCM is mainly caused by gene mutations (sometimes called variants or markers). Not all HCM is linked to a specific variant, and we believe more mutations will be identified in the future. 

In recent studies at large HCM Centers, about 40% of those tested had a gene mutation known to cause HCM. As of 2023, 60% will not have a mutation currently identified as causing HCM. It is still believed that HCM is a genetic disorder that families can pass down – even if the mutation is currently unknown. 

Your genetic test can show one of three results:

  • Positive / Mutation identified (you have a known variant). 
  • Negative / No mutation identified (you do not have a known variant).
  • VUS (a variant of uncertain significance whose meaning is still evolving). It’s a bit confusing, but as researchers learn more, a VUS can be reclassified as a positive or negative.

If your genetic test is positive, this information can be used to screen family members to see if they have the same variant.  Your children, parents, and siblings can be tested for your variant, and if they don’t have it, they can skip clinical tests (echocardiogram, etc.) unless they develop heart symptoms. 

A negative genetic test DOES NOT take away your HCM diagnosis ,  and it DOES NOT mean that your family can safely avoid clinical screening for HCM  (echocardiogram, EKG, and an exam by a cardiologist). Researchers are still discovering variants that may cause HCM and are starting to look into combinations of two or more genetic variants ( polygenetic ) that could cause HCM. If you do not have a known variant, your close relatives must be screened regularly using clinical tests to see if they develop HCM. 

Once you’ve gone through our free  Intake  process, we will invite you to join our new  Nest  education program.  For a great explanation of genetic testing in HCM, sign up for the Nest portal when you’re invited.

Knowing your mutation may allow gene therapy to treat your HCM in the future. Clinical gene therapy trials for those with a mutation on MYBPC3 have started! We expect other common HCM variants (such as MYH7, etc.) to be included in future clinical trials.

A last thought: many people who test positive for one of the known variants say, “I have the gene for HCM,” but this is misleading. They have a mutation on one of many genes that may contribute to HCM.For more information about genetics and genetic testing, please visit the HCMA website at  https://4hcm.org/genetic-testing-an-overview/  and  https://4hcm.org/genetic-testing-other-considerations/.

HCMA Blog

April 30, 2025
Medical Management means using medicines and other non-invasive therapies to relieve symptoms. It's exciting that new treatments for HCM are being studied and that the FDA approved Camzyos in 2022! HCM can cause various symptoms depending on how stiff the heart is, how much scarring (fibrosis) there is, and whether there is obstruction. Some people have no noticeable symptoms. Common symptoms are chest pain/pressure, shortness of breath, lightheadedness, fatigue, palpitations, and brain fog. Syncope (fainting) is dramatic but not as common as the other symptoms. Medications are the first-line treatment for symptoms of HCM. If patients can't take one class of medication, they can try a medication from a different class. Here are some medications used to treat HCM and what they're for: Beta Blockers - make your heart beat slower and relax better. They allow the heart to fill more completely between beats. They can lower blood pressure and relieve symptoms. Calcium Channel Blockers - used to lower blood pressure and slow the heart rate. May reduce symptoms from obstruction in HCM. Myosin Inhibitors - cause the heart to beat with less force. They may reduce obstruction and septal thickness in some patients. Camzyos (mavacamten) is the first of this class of medication. For more information, click HERE . Antiarrhythmics - help to restore normal rhythm in the heart. Blood Thinners - anticoagulants and anti-platelets make it harder for blood to clot. They are prescribed to reduce the risk of stroke. This risk is higher in patients with afib, aflutter, and artificial heart valves. Diuretics , or "water pills," help the kidneys get rid of extra water and salt, reducing swelling in the body. Sodium Channel Blockers - may reduce gradient in obstructive HCM and can treat chest pain. Some also act as antiarrhythmics. Antibiotics - treat or prevent bacterial infections. In HCM, they may be given before dental work to prevent infective endocarditis. To learn more and see the side effects of these medications, click HERE .
On a green background, a line drawing of a head that has complicated arrows pointing outwards
By Gordon Fox April 25, 2025
Part 2 of a series on making decisions in HCM. A key reason is that decision making is so difficult is that most decisions involve more than one risk.
Hypertrophic Obsctructive Cardiomyopathy
By Erica Friedman April 22, 2025
Bristol Myers Squibb announces that Camzyos has been approved for Obstructive Hypertrophic Cardiomyopathy in Japan.
More Posts