Through WES analysis in two members affected by AF (Family 1: III-1 and IV-1) and one healthy member (Family 1: III-2), we found that, at the mapped locus, only the variant chr7:35280609T>C (GRCh37.p13: NC_000007.13), equal to chr7: 35215533T>C (GRCh38.p14: NC_000007.14) or NM_001077653.2: c.695A>G; p.(His232Arg) in TBX20, was identified and confirmed via Sanger sequencing assay to co-segregate with AF in Family 1. The gene discussed is TBX20; the disease is atrial fibrillation.