Genetic testing uncovers the cause of a family's cardiac disorder

Had it not been for genetic research, my children and I would not know what really causes our condition. Other families have lost children before they found out what they were dealing with. We didn't. We were fortunate.

- Kim Thomas

For Kim Thomas, a physical education teacher who loves to work out, being active is a central part of her life. The same goes for her three children who enjoy sports of all kinds.

After being diagnosed with a potentially fatal heart condition, Kim and her kids thought they would have to change their active ways, permanently. But, genetic testing gave them the information they needed to make informed choices about their health, as well as the chance to resume their fast-paced lives.

Uncovering a problem

In 1996, Kim's mother died in her sleep at the age of 55. The cause of her death was not found, but Kim was determined to learn more. "It really bothered me that she died so young. I wanted to find out what happened." says Kim.

Kim gathered her mother's medical records and reviewed them with a physician. After finding suspicious results in some of her mother's cardiac tests, the physician recommended Kim have an electrocardiogram (ECG) to study her heart's rhythm.

The results indicated there was a problem. Kim, who lives in Bemidji, Minn., was referred to a cardiologist in Fargo, N.D. From her ECG test, the cardiologist diagnosed long QT syndrome, a rare and sometimes fatal disorder of the heart's electrical system. In long QT syndrome, the heart muscle takes more time than normal to electrically recharge between beats. This electrical glitch results in an irregular heart rhythm.

Because the condition often is inherited, Kim's children also were tested. The results were the same; all three had long QT syndrome. The family was then referred to Mayo Clinic where they went through more tests to determine how to best manage the disorder.

"They knew we had long QT syndrome, and, at that point, they thought our highest risk of death was when we had bursts of adrenalin in our bodies," says Kim.

Kim and her children were put on beta blockers, a type of medication that slows the heart rate and helps prevent the dangerously fast heartbeats that can occur in times of stress, fear or exertion. The medication brought the Thomas's previously active lives to a standstill.

"Because of the medication, we couldn't get our heart rates up to the point we needed to be really active," says Kim. "My kids had to quit their sports. I had to quit all of my workouts and cut back on activity in my classes. We just physically couldn't do it."

Learning more through genetic testing

The family felt the sacrifice to be worth it if the medication kept their irregular heart rhythms at bay. However, a little more than a year later, genetic testing was available to shed new light on the family's medical condition. Results of a blood test were able to show mutations in the genes known to cause inherited long QT syndrome.

"They did the genetic testing and discovered that the gene mutation we have that causes our long QT is not connected to adrenaline," says Kim. "It's not exercise that will kill us, it's sleep. That made more sense because that's how I lost my mom."

Armed with this new information, the family's physicians took them off the beta blockers and instead offered the only alternative for the Thomas's type of long QT syndrome: implanting a defibrillator that would monitor for and, if necessary, stop a potentially fatal arrhythmia.

"It has been wonderful since we've had the defibrillators implanted. The kids are back into tennis and gymnastics. I'm working out again." says Kim. "Had we not had the genetic testing, we wouldn't have been given this chance of enjoying an active life again."

A more sobering benefit of the genetic testing also is clear to Kim. "Had it not been for genetic research, my children and I would not know what really causes our condition," she says. "Other families have lost children before they found out what they were dealing with. We didn't. We were fortunate."

Looking to research for more options

With only two follow-up visits to Mayo Clinic required each year, Kim and her kids have returned to their normal routines. They hold out hope, though, that researchers will continue learning more about long QT syndrome.

Says Kim, "The defibrillators are what we'll have for a while, until the research finds something better for us."