TTN and atrial fibrillation: Ahlberg et al. performed whole-exome sequencing in 24 families with aggregation of AF (59) and discovered that the frequency of titin-truncating variants (TTNtv) in cardiac transcripts was significantly higher in the individuals with AF compared to an unaffected referent group (16.7 vs. 0.5%, P = 1.76 × 10−6).