Scientists have identified a genetic mutation causing the irregular heartbeats that characterize atrial fibrillation (AF). Nearly one out of every 20 individuals over age 65 suffer from this cardiac arrhythmia, which is increasing in prevalence as the population ages. When left unchecked, AF can lead to heart muscle dysfunction, embolism, ventricular arrhythmia, and heart failure. Studying families with a rare inherited form of AF, a collaborative research team composed of scientists in China and France has identified the disease-causing gene as KCNQ1, which encodes a protein subunit of an ion channel controlling the movement of charged potassium through a cell membrane. The discovery is reported in the 10 January 2003 issue of Science.
This new understanding of the molecular basis of atrial fibrillation may lead to better pre-symptomatic diagnosis of the disorder and to the development of new therapies, according to corresponding authors, Yi-Han Chen of Tongji University, Shanghai, China and Shi-Jie Xu of Chinese National Human Genome Center, Shanghai, China.
The scientists studied a four-generation family in China with a history of AF. Of the 44 living members of this family from both rural villages and nearby cities in northern Shandong Province, sixteen have cases of AF, all of which the researchers confirmed were hereditary. Gene mapping studies led the researchers to the critical region of chromosome 11 that was linked to AF. Sequence analysis revealed that there was a specific nucleotide substitution in the KCNQ1 gene in all of the family members affected with
Contact: Lisa Onaga
American Association for the Advancement of Science