Gene mutations, atrial fibrillation, and the elusive cigar

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The term lone AF describes nonsyndromic atrial fibrillation that occurs in the absence of underlying structural heart disease or predisposing clinical conditions. A hereditable component leading to conduction abnormalities in AF has long been suspected, and epidemiological evidence of elevated risk for AF among first-degree relatives of probands was recently documented. The first AF-associated molecular defect was found in an affected Chinese family; initial studies narrowed the chromosomal location by linkage analysis, and Yihan Chen et al. found a specific gain-of-function mutation in KCNQ1, the gene for the alpha subunit of potassium channels.