Loss-of-Function Variants in Cytoskeletal Genes Are Associated with Early-Onset Atrial Fibrillation

• Main Authors: Oliver Bundgaard Vad, Christian Paludan-Müller, Gustav Ahlberg, Silje Madeleine Kalstø, Jonas Ghouse, Laura Andreasen, Stig Haunsø, Arnljot Tveit, Ahmad Sajadieh, Ingrid Elisabeth Christophersen, Jesper Hastrup Svendsen, Morten Salling Olesen
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Journal of Clinical Medicine
• Subjects: atrial fibrillation; genetics; arrhythmia; cardiology; next-generation sequencing; cardiomyopathy
• Online Access: https://www.mdpi.com/2077-0383/9/2/372

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and it is associated with an increased risk of heart failure, stroke, dementia, and death. Recently, titin-truncating variants (TTNtv), which are predominantly associated with dilated cardiomyopathy (DCM), were associated with early-onset AF. Furthermore, genome-wide association studies (GWAS) associated AF with other structural genes. In this study, we investigated whether early-onset AF was associated with loss-of-function variants in DCM-associated genes encoding cytoskeletal proteins. Using targeted sequencing, we examined a cohort of 527 Scandinavian individuals with early-onset AF and a control group of individuals free of AF (<i>n</i> = 383). The patients had onset of AF before 50 years of age, normal echocardiogram, and no other cardiovascular disease at onset of AF. We identified six individuals with rare loss-of-function variants in three different genes (dystrophin (<i>DMD</i>), actin-associated <i>LIM</i> protein (<i>PDLIM3</i>), and fukutin (<i>FKTN</i>)), of which two variants were novel. Loss-of-function variants in cytoskeletal genes were significantly associated with early-onset AF when patients were compared with controls (<i>p</i> = 0.044). Using publicly available GWAS data, we performed genetic correlation analyses between AF and 13 other traits, e.g., showing genetic correlation between AF and non-ischemic cardiomyopathy (<i>p</i> = 0.0003). Our data suggest that rare loss-of-function variants in cytoskeletal genes previously associated with DCM may have a role in early-onset AF, perhaps through the development of an atrial cardiomyopathy.