Data expand clinical utility of deCODE's DNA-based risk tests for heart attack, AF and stroke

In 2007, deCODE discovered two SNPs on chromosome 4q25 that double the risk of atrial fibrillation (AF), and launched its deCODE AF™ test to detect these variants. Given that AF is underdiagnosed, one principal purpose of this test is to enable the identification of people at higher risk and to monitor them more intensively and to put those who exhibit AF on appropriate medication.

At this year's AHA, deCODE and independent groups will present data from studies that expand the understanding of how deCODE AF can contribute to better clinical practice. deCODE's original discovery of the 4q25 SNPs was replicated and validated in several European and U.S. case-control cohorts. Since then, the company has published findings that the SNPs in deCODE AF also confer risk of ischemic stroke, with highest risk for cardioembolic stroke. At AHA the company will discuss the implications of linking these markers not only with risk of AF, but also to risk of stroke and non-cardiogenic stroke. One implication is that AF appears to cause an even larger proportion of stroke than originally thought. This strengthens the case for going beyond standard cardiac monitoring, for hospitalized and discharged patients who have suffered stroke or transient ischemic attack (TIA), and for the prescription of warfarin, rather than Plavix™ or aspirin, for those with AF. deCODE will also present data on the utility of deCODE AF™ for detecting recurrent AF.

Researchers from Cleveland Clinic have conducted their own study of the link between the 4q25 markers and AF, and will look at correlations between these variants and mRNA expression profiles of the nearby PITX2 gene, which is expressed in atrial cardiac muscle. Groups from Brigham and Women's Hospital and Vanderbilt University examine the utility of testing for these variants to predict likelihood of developing AF after cardiac surgery, a complication that is associated with increased morbidity and mortality. Determining which patients may most benefit from prevention therapy with anti-arrhythmic medications is important because these drugs have side effects that make them unsuitable for use in all patients.

Among the talks relevant to the utility of deCODE MI™ and deCODE AF™ are those listed below. The full abstracts and contents of these talks are strictly embargoed for public dissemination until their time of presentation, as noted per AHA guidelines.

Sunday, November 9

9:00-9:20am, Room 267-268, presentation number 275, "Genetics of coronary heart disease and risk factors." Presenter: Kari Stefansson, deCODE genetics.

4:15-4:30pm, Room 225-227, presentation number 1171, "Risk variants for atrial fibrillation on chromosome 4q35 associate with non-cardiogenic stroke, suggesting that AF is a much greater cause of stroke than previously recognized." Presenter: Jeff Gulcher, deCODE genetics.

Tuesday, November 11

9:30-9:45am, Room 355, presentation number 4985, "Are all patients considered 'low risk' for coronary heart disease really low risk? An analysis from the Atherosclerosis Risk in Communities (ARIC) study." Presenter: C.M. Ballantyne, Baylor College of Medicine