PITTSBURGH (NewsRadio 1020 KDKA) – Imagine that your child passes out or dies during exercise or playing a sport. While it is unusual, a rare heart defect is what killed Marathon runner Kyle Johnson, 23, and there are warning signs you can watch for in your child.

“Fainting during exercise is  probably the biggest red flag that parents should pay attention to,” says KDKA-TV’s Dr. Maria Simbra. Other signs include being overly winded, shortness of breath, or family history of unusual early deaths.

KDKA-AM’s Larry and John talked to Dr. Maria Simbra about this congenial heart defect and what causes it.

“In this young man’s case, it was a problem where the blood vessels that supply the heart with blood came off in the wrong place. It was something he was born with.”

Luckily, this defect is repairable if caught early. For instance, another local boy passed out during a track meet, and tests originally came back negative.

“They went back and did some fancier tests and they found the same problem that the young man had in the half-marathon, where he had an abnormal vessel coming off of his heart in the wrong place,” says Dr. Simbra. “He had open heart surgery, they fixed it, and he’s back to his sports.”

Since most people catch this problem or have a health issue early in their lives, this usually affects younger people, but Dr. Simbra says everyone should  see a doctor if they exhibit any symptoms.