Researchers of the international science consortium QTSCD (QT interval and Sudden Cardio Death) with Dr Arne Dfenfer of the institute of Human Genetics at Helmholtz Zentrum Munchen have identified 10 gene variants which predispose to an elevated risk for arrhythmias and SCD. They have located nine new genetic variants, and confirmed the role of another recently identified variant, that affect the time that it takes for the heart to reset itself after each beat. The duration of this QT interval, as it is called, is routinely measured by electrocardiogram (EKG), and lengthened QT interval is a known risk factor for sudden death. The results were published in this week's Nature Genetics.
The international team of researchers, part of the QTGEN Consortium, studied 15,000 people from Germany, Italy and the U.S. These are all long-term studies of thousands of adults whose heart health has been tracked for decades. The study's analysis showed that the more of these genetic risk variants a person had, the more likely a QT interval problem was present.
Some people with too long or too short QT intervals are vulnerable to heart rhythm disturbances that can on occasion lead to sudden death. This can happen at any age, even in young, apparently healthy, fit athletes who have abnormally short or long QT intervals. In most cases the heart just stops beating without any warning. There are some known risk factors, such as female gender, fainting episodes after physical activity or emotional excitement, and a family history of deaths during exercise or unexplained deaths in otherwise healthy relatives.
"But we're interested in finding the actual genes that predispose people to sudden cardiac death, in order to have more specific predictors," Dr. Kenneth Rice said, assistant professor of biostatistics at the University of Washington School of Public Health.
Surprisingly, almost half of the newly discovered genetic variants were in areas of the genome not previously associated with heart rhythm disturbances.
Rice said that, because of this genetic revolution in epidemiology, the study of the rates and risks illnesses in large populations, people can expect to see more reports soon on discoveries of genetic variants for conditions related to heart and blood vessel disease, such as high blood pressure, stroke, diabetes, and obesity.
For more information read the original article from:
Nature Genetics 41, 399 - 406 (22 Mar 2009), doi: 10.1038/ng.364, Article
