deCODE Discovers Second Common Genetic Risk Factor for Atrial Fibrillation and Stroke
News Jul 14, 2009
Scientists at deCODE genetics and colleagues from Europe and the United States report the discovery of a common single-letter variant in the sequence of the human genome (SNP) conferring increased risk of atrial fibrillation (AF) and stroke.
The findings will be integrated directly into the deCODE AF™ reference laboratory test for gauging individual risk of AF and stroke and helping to identify stroke patients who may benefit from enhanced monitoring for AF. The study is published online in Nature Genetics at www.nature.com/ng.
The new SNP is in the ZFHX3 gene on chomosome 16q22, and the more than one third of people of European descent who carry one copy are at approximately 20% greater risk of AF and cardioembolic stroke than are individuals who carry none.
AF is the most common type of cardiac arrhythmia, and is a major risk factor for stroke. Because AF is often intermittent and difficult to detect, gauging genetic susceptibility can help doctors to decide which of their stroke patients might benefit from longer-term monitoring for AF following a stroke. Those with stroke due to AF may be given different therapy than they would otherwise. This is the purpose of deCODE AF™, at the heart of which is the major AF and stroke variant discovered by deCODE on 4q25.
These findings are the result of deCODE’s program to build on this work and to find new risk variants. After expanding their genome-wide association study in Iceland, the deCODE team took the top SNPs outside the 4q25 region and typed them in case-control cohorts from Iceland, Norway and the United States. This confirmed the ZFHX3 SNP as a risk variant for AF.
Analysis in stroke cohorts from Iceland, Germany, Sweden and the UK demonstrated that this SNP was associated with increased risk of stroke, particularly cardioembolic stroke.
“This is an important discovery and all the more gratifying because we can integrate it straight into a test that is already helping to improve patient care in the clinic.
As with our 4q25 variant, this latest discovery has been replicated in numerous populations by us and others, and the connection to cardioembolic stroke is yet further evidence that we are putting our finger on an important pathway involved in AF and stroke risk.
The ability to routinely test for these risk factors means that we can understand whom we should screen intensively for AF and then prescribe the drugs most suited to the cause of a particular patient’s disease. This is the sort of personalized medicine that genetics is enabling – individualized care that may mean not only better outcomes but significant potential savings to the healthcare system. Discoveries like this are the foundation upon which this transformation is being made,” said Kari Stefansson, CEO of deCODE.