A new genetic variant associated with increased susceptibility for atrial fibrillation, a prominent risk factor for stroke and heart failure, is reported in two studies published online in this week's Nature Genetics.

Atrial fibrillation (AF) is a type of chronic heart disease characterized by an electrical defect of the heart's upper chambers that causes ineffective beating of the heart and incomplete pumping of blood. This defect leads to blood pooling and clotting, which can result in a stroke if a blood clot leaves the heart and becomes lodged in a brain. In the United States and Europe, one in four individuals has a lifetime risk of developing AF.

Emelia Benjamin, Daniel Gudbjartsson and colleagues scanned the genomes of thousands of individuals and discovered a new risk variant in the gene ZFHX3 that is associated with slightly elevated risk for developing AF. More research is needed to determine how ZFHX3 may affect heart function in individuals with AF.