After filtering by the allele frequency (<0.01% in the general population according to the public database), we identified two susceptibility rare variants, c.-324C>A (NM_018400.4, rs976125894) and c.-303C>T (NM_018400.4, rs1284768362), in the first exon and the 5′UTR region of SCN3B gene in two unrelated patients clinically diagnosed as lone AF (Figure 1a,b). This evidence concerns the gene SCN3B and atrial fibrillation.