Following genetic testing of the family which confirmed the absence of mutations in genes known to cause familial AF (GJA5, KCNA5, KCNE2, KCNJ2, KCNQ1, KCNH2, NPPA and SCN5A), the possibility of a mutation in a novel gene was considered. This evidence concerns the gene KCNQ1 and atrial fibrillation.