Does Atrial Fibrillation Follow Function?

In this issue of Circulation: Arrhythmia and Electrophysiology , Hayashi et al1 present an interesting study evaluating the role of rare genetic variants in cardiac ion channels in the development of lone atrial fibrillation (AF).Article see p 1095In recent years, compelling data has demonstrated that AF is heritable. Several studies have shown that mutations and rare variants, especially those located in genes encoding cardiac ion channels, are associated with AF. Additionally, genome-wide association studies have identified many common genetic variants that are associated with an increased risk for AF. Although most patients with AF present with comorbidities, such as hypertension, coronary artery disease, or heart failure, many younger patients have isolated or lone AF.2 Given that these younger patients do not have an obvious cause for their arrhythmia, it has been assumed that genetics may play a significant role in the pathogenesis of lone AF. Thus, many investigators have focused on individuals with lone AF to obtain a unique window into the genetic basis of the arrhythmia.Over the last 10 years, many studies have considered individual candidate genes for AF and identified mutations in a wide range of genes encoding ion channels, signaling molecules, and transcription factors among others.3 These studies …