Genetic rarity: All 3 Byler children inherit the same cardiomyopathy heart defect

Two Byler children get heart transplants while a third manages with medication. Genetic tests showed it was unlikely the youngest would be born with cardiomyopathy.

Elizabeth and Andrew Byler were devastated when their first child, Emily, was diagnosed with a congenital heart defect. A few years later, they were shocked to discover their second child, Ethan, also had a heart defect and would require a transplant.

But sometimes there are three sides to every story.

In February 2017 their third child, Eva, was born.

“At first, Eva was a picture of health,” Elizabeth said. “But I’m a worrier, so I constantly watched her to see if she experienced any symptoms.”

An echocardiogram revealed that she had cardiomyopathy and an atrial septal defect — a hole in her heart. The diagnoses were overwhelming to the family.

“All of my fears came true,” Elizabeth said.

Chances were slim that Eva would have cardiomyopathy

The Bylers had spoken to a genetics counselor and cardiologist and understood that their chance of having a third child with cardiomyopathy was slim, but still possible.

The likelihood of having three children born with a heart condition is extraordinarily rare and depends mostly on the parents’ genetic makeup, according to Joshua Sparks, M.D., pediatric cardiologist with UofL Physicians and heart failure and transplant director at Norton Children’s Heart Institute, affiliated with the University of Louisville.

“A sibling only has an increased risk if his or her parents have the abnormal gene,” Dr. Sparks said.

The oldest, Emily, was diagnosed with dilated cardiomyopathy (DCM) in 2012. Now 6 years old, she is able to manage her condition with medications, but may need a transplant eventually.

When Ethan was born, doctors were able to recognize symptoms of DCM quickly. At just 7 months old, he received the same diagnosis as his older sister. Not long after, he became the first child in Kentucky to receive a Berlin Heart — an external mechanical pump that kept him alive until he received a heart transplant in March 2015.

After surviving the challenges of Ethan’s journey, including a difficult bout of respiratory viruses, Elizabeth and Andrew were nervous to go down that path again with Eva.

“It’s heartbreaking to see a child go through this experience, and it’s a strain on the whole family,” Elizabeth said.

The long journey to a heart transplant

At about 7 months old, Eva was admitted to Norton Children’s Hospital on Sept. 11, 2017, and stayed for a month.

When she went home to Hart County, Kentucky, Eva’s symptoms — clammy skin and cold sweats — intensified. She was readmitted to Norton Children’s Hospital the next day.

Her pediatric heart specialists determined she would need a heart transplant. They didn’t know it at the time, but Elizabeth and Andrew would be in the hospital with Eva awaiting a transplant for eight months.

The long stay meant Norton Children’s Hospital became Eva’s home during the first year of her life.

“Most of her ‘firsts’ happened in the hospital, so we tried to make it as normal as possible for her so she didn’t miss any milestones, like taking her first steps,” Elizabeth said.

On Eva’s first birthday, child life therapists brought a “My Little Pony” themed cake to the Byler family to celebrate. Small, meaningful gestures like this kept the Bylers’ spirits up.

After a few mild viruses, lots of medication and many months in the hospital, Eva received a heart transplant in May 2018.

Read more: Eva’s heartbeat put in stuffed animals for family back home

Learn more: What is cardiomyopathy and how the specialists at Norton Children’s Heart Institute treat it

The same genetic mutation, but different effects

Even though all three siblings have a heart condition in common, their journeys have been vastly different.

“In the case of the Byler family, they all have the exact same genetic mutation, but all three children presented it at different ages with different severities of the disease,” Dr. Sparks said.

Norton Children’s Heart Institute

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According to Dr. Sparks, doctors are limited in understanding how genetic abnormalities lead to disease; for instance, Eva’s cardiomyopathy is explained by her genetics. The atrial septal defect, however, likely isn’t inherited.

“There are complex genetics … that can lead to multiple types of congenital heart defects that we cannot really describe just yet,” Dr. Sparks said.

His advice for relatives of children with a heart defect: Get a genetic test.

“In general, siblings and any first-degree relatives of an affected individual should undergo clinical screening and, if a positive genetic test is found, then genetic screening should occur as well,” Dr. Sparks said. More often than not, a genetic test won’t reveal a child’s cardiomyopathy.

At home with her new heart

Eva is now back at home adjusting to life with a new heart as she nears her second birthday. Emily and Ethan are thrilled to have their baby sister home.

“Eva is a little sunshine,” Elizabeth said. “She’s a fighter who is full of life now, and that’s all we could want.”

The Bylers are particularly thankful to have Dr. Sparks as the physician who has been with them through all three kids’ journeys.

“Their resilience has no equal,” Dr. Sparks said.