Gene Mutation Tied to Inherited Atrial Fibrillation
WEDNESDAY July 9, 2008 -- A gene mutation linked to one family's hereditary form of atrial fibrillation may help researchers find better ways to predict, prevent and treat the heart rhythm problem, according to a new report.
The mutation -- a flaw in the DNA sequence -- was discovered by Mayo Clinic researchers studying a large family with an inherited form of atrial fibrillation in 11 relatives. Collaborators at the University of Iowa later confirmed the mutation's role in altering the electrical properties of the heart through an animal model.
The findings are published in the July 10 online version of the New England Journal of Medicine.
More than 2 million Americans have atrial fibrillation, the most common type of irregular heartbeat. It happens when the heart's two upper chambers beat irregularly and out of synch with the two lower chambers. This causes irregular, often rapid heart rates and can lead to inadequate blood flow to the body, putting the person at an increased risk of stroke. The condition can be treated with medications or surgery.
While risk factors for developing atrial fibrillation, such as high blood pressure or structural heart disease, are known, they are not always present.
"We know that some patients develop atrial fibrillation at a younger age without an apparent underlying cause, suggesting a hereditary basis for their disease and prompting research to identify gene mutations," senior study author Dr. Timothy Olson, a pediatric cardiologist at the Mayo Clinic, said in a news release issued by the facility.
Investigators gathered and analyzed clinical and genetic data from the 11 affected and five unaffected family members. All 11 with atrial fibrillation shared a mutation in the gene that codes for atrial natriuretic peptide (ANP), a hormone that helps regulate body water, sodium and vascular tone. The mutation damaged the heart's electrical properties and caused higher-than-normal blood level concentrations of the peptide.
"While the family members with atrial fibrillation have a rare mutation, the study findings provide insight into pathways that may be applicable to people in the general population with atrial fibrillation," study first author Dr. Denice Hodgson-Zingman, an electrophysiologist at the University of Iowa, said in the same news release. "It is intriguing that a defective circulating hormone can cause atrial fibrillation. It gives us a potential new target for developing treatments."
Posted: July 2008