Both index patients were free of mutations in genes previously associated with AF (KCNQ1, KCNH2, KCNN3, KCNA5, KCNE2/3/5, KCNJ2,5, SCN5A, SCN1-3B, ANP, and LMNA). This evidence concerns the gene KCNQ1 and atrial fibrillation.