Genetics and Family Risk: What to Know if You Have Hypertrophic Cardiomyopathy (HCM)

Hypertrophic cardiomyopathy (HCM) is a genetic heart condition that can potentially cause serious complications. The condition runs in families, so if you’ve been diagnosed, you may have concerns about how other people in your family may be impacted as well.

Fortunately, screening tools and genetic testing can give your loved ones the information they need, so they can take steps to protect their heart health.

“It’s an autosomal dominant disease, which means it has a 50 percent chance of being passed on to other family members,” says Matthew Martinez, MD, the director of Atlantic Health System Sports Cardiology at Morristown Medical Center in Morristown, New Jersey. “In any patient who has a clinical diagnosis of hypertrophic cardiomyopathy, all first-degree relatives are also at risk.” So when you have HCM, there’s a high likelihood that your children or siblings may have the condition as well.

That said, HCM severity and symptoms can vary significantly from person to person, even those who are related. “Within a family, you can have someone who might need surgery, someone who might be asymptomatic, and someone who might need a heart transplant,” says Dr. Martinez.

HCM doesn’t always cause symptoms. It’s also common for people with mild symptoms, like shortness of breath while exercising or fatigue, to ignore them or think they’re a result of something else.

“People might think ‘I’m just getting older,’ or ‘I’m not in good shape,’ or ‘I’m tired because my kids are wearing me out,’” says Martinez. “You come up with reasons to not be concerned.”

When you have HCM, screenings can determine whether other people in your family have the condition as well. “Regular screenings and follow-ups are important, even for individuals who feel completely well,” says Dr. Steitieh.

• Echocardiogram This ultrasound imaging test shows how well the heart is pumping blood.
• Electrocardiogram (ECG/EKG) This test uses sensors placed on the skin to measure the heart’s electrical activity. It can detect irregular heart rhythms and heart thickening.
• Physical Exam and Family History During this exam, a cardiologist can check for irregular heartbeats and learn about HCM in a person’s family.

Experts like Steitieh and Martinez agree. “We’ve been able to prove that by screening, we make more diagnoses,” says Martinez. And when you know you have HCM, even if you’re asymptomatic, you and your care team can determine the best way to treat it, thereby reducing your risk of serious complications.

“A diagnosis leads to treatment, and treatment leads to better outcomes,” says Martinez.

Genetic testing differs from screening, but it can be a valuable tool for some families in which HCM is prevalent.

The decision to undergo genetic testing is a personal one. Family members don’t need to have genetic testing in order to be screened for HCM. What’s more, not being a carrier doesn’t guarantee a person is safe from HCM.

“We have to understand its limitations, which is mainly that we don’t know every HCM disease-causing gene,” says Steitieh.

• Hypertrophic cardiomyopathy (HCM) is a genetic condition; first-degree relatives (parents, siblings, and children) of a diagnosed individual have a 50 percent chance of inheriting the mutation.
• Because HCM is often asymptomatic or presents with mild symptoms like fatigue and shortness of breath during exercise, an estimated 85 percent of people with the condition remain undiagnosed, which increases the risk of serious complications or sudden cardiac death.
• Clinical screenings, including echocardiograms, EKGs, and physical exams, are vital for early detection and should be repeated every 1–3 years for children and every 3–5 years for adults who have a family history of the disease.
• Genetic testing can identify specific gene mutations to determine which family members are truly at risk. It’s a personal choice and has limitations, because not all HCM-causing genes have been discovered.