Kane: Each of the two genes that we are reporting here have a variant form of the gene, structurally different, which is more commonly found in people with heart disease, suggesting very strongly that that gene has an effect on the risk of heart disease.
Narrator: One of the genes is linked to clotting, which can lead to a heart attack. And Kane says the heart attack risk from both the genes they've identified is comparable to the risk from being a heavy smoker.
Kane: Smokers who smoke a pack of cigarettes a day will experience an approximate doubling of the risk of heart attack, but each of these genes contributes about that much increased risk of heart attack as well.
Narrator: For Science Today, I'm Larissa Branin .