HOUSTON --Until actor John Ritter died, few people had heard much about the problem that killed him. Now in a surprising twist of events, his sudden death has actually saved people's lives. "He had chest pains and nausea and was taken to the emergency room which was right across the street from where he was filming at Disney Studios and they assumed he was having a heart attack," said Ritter's wife, actress Amy Yasbeck. But it wasn't a heart attack. John Ritter had an aortic dissection, a tear in the main blood vessel coming out of the heart. He died a few hours later. "The tragic part of it is, it can be prevented. No one need die prematurely of acute aortic dissection if we know who's at risk," said Dr. Dianna Milewicz, University of Texas-Houston. "I don't want it to sneak up on anybody else," said Yasbeck. She is working with Dr. Milewicz and her UT-Houston team to find the genes that lead to Ritter's death. In these freezers are samples from 10,000 people which have helped them isolate four of the genes that are related to aortic aneurysm. "All the genes we've identified lead to a high risk of aortic dissection," said Dr. Milewicz. However, there are several more. So Yasbeck's 11-year-old daughter Stella and Ritter's three older children are in the gene study. Scientists get DNA from a saliva sample. Since Ritter's death, his brother Tom had an aortic aneurysm but it was caught and repaired with surgery. "He would have died of exactly the same thing his brother died of," said Yasbeck. They think John's father, Tex Ritter the singing cowboy, may have died of an aortic dissection, too. Now everyone in the family is watching for it. "Stella is just like the big kids - on a yearly scanning schedule," said Yasbeck. And she has already been hearing from people who say her husband's death saved their lives. "People have been throwing John's name out there as a safeguard, saying, 'How do I know it's not that John Ritter thing?' And it's being found that way," said Yasbeck. If you are concerned about aortic disease, you can be tested for the four newly discovered genes by asking your doctor for it or going to a geneticist. It's a saliva test.