Q&A: Unlocking Genetic Causes of Heart Disease

Newswise — LOS ANGELES (April 6, 2022) -- Physician-scientists from the Smidt Heart Institute at Cedars-Sinai are working to identify genetic risk factors for cardiomyopathy—a collection of conditions that reduce the heart’s ability to pump blood to the rest of the body—and how inherited forms of the condition can be detected at earlier stages.

“Several forms of cardiomyopathy can have a genetic component,” said Eugenio Cingolani, MD, director of the Cardiogenetics Program in the Smidt Heart Institute and associate professor of Cardiology. “These include the most common form, dilated cardiomyopathy, in which the heart becomes enlarged and does not function normally.”

Dilated cardiomyopathy affects around 1 in every 300 people and can lead to heart failure.

“In many cases, dilated cardiomyopathy results from an inherited variation in a gene that is needed for heart function or structure,” said Evan Kransdorf, MD, PhD, associate director of Heart Transplant Research and Education at Cedars-Sinai. “This form of cardiomyopathy is a principal cause of clinical heart failure and a leading indicator for heart transplant.”

The Cedars-Sinai Newsroom asked Kransdorf and Cingolani to share the latest patient advice and research news regarding dilated cardiomyopathy and other inherited forms of the condition.

Newsroom: What have you learned recently about dilated cardiomyopathy?
Kransdorf: In many cases there is no clear cause for dilated cardiomyopathy, a condition called idiopathic dilated cardiomyopathy. In a study recently published in the Journal of the American Medical Association (JAMA), we sought to find out how frequently idiopathic dilated cardiomyopathy is present in the parents, siblings, or children of a person diagnosed with the condition. Looking at a diverse group of patients, 43% Black and 8% Hispanic, we found that out of 10 persons with idiopathic dilated cardiomyopathy, we would expect about three of those persons to have family members who also have the disease. The prevalence of familial involvement was higher in persons of Black ethnicity, at 39%, compared to those of white ethnicity and Hispanic ethnicity, at 28%.

Newsroom: What might explain the prevalence of dilated cardiomyopathy in the Black population?
Kransdorf: Studies exploring human genetic variation, such as the 1000 Genomes Project, have shown that individuals of African ancestry have more inherited genetic variations than those in other ethnic groups, so it is possible that dilated cardiomyopathy is more likely to run in families of African ancestry, but only further research will tell us if this is true.

Newsroom: Based on these results, what are your recommendations for patients?
Kransdorf: These results highlight that a diagnosis of dilated cardiomyopathy is important not just for the affected person, but also for their family members. If you have a family member with dilated cardiomyopathy, screening of all parents, siblings, and children is recommended by the American Heart Association, a guideline Cedars-Sinai follows, too. This usually involves a visit with a cardiologist to undergo an electrocardiogram and echocardiogram. Screening of family members is even more important for persons of Black ethnicity, given the increased frequency in this population.

Cingolani: In some cases, genetic testing may be beneficial, and it can be ordered and interpreted in conjunction with a genetic counselor. Genetic testing helps confirm the patient’s diagnosis and tells us which of the patient’s family members should also be screened for the condition. It can also offer some information about how their condition may progress and the forms of treatment that might be most beneficial. In addition, knowing the affected gene and the chances it might be inherited can be useful for family planning.

Newsroom: Why are screening and early detection of dilated cardiomyopathy so important?
Kransdorf: Like many conditions, dilated cardiomyopathy seems to be more responsive to treatment when it is identified at earlier stages. While there is a genetic component, lifestyle factors likely play a very important role in affecting when persons will develop the disease.

Cingolani: Hypertension and obesity can contribute to weakening of the heart muscle in those with an inherited tendency toward this condition. Following a heart-healthy diet low in sodium and largely plant-based, daily light exercise, keeping weight and blood pressure at healthy levels, and avoiding smoking and excessive alcohol consumption can reduce risk for these things. Close follow-up with a cardiologist who can suggest additional treatment as needed is also important. 

Read more on the Cedars-Sinai Blog: “Broken Heart” Syndrome Spikes During COVID-19