In addition, a Sanger sequencing assay of TBX20 was completed in Family 2 (Figure 3) and in another cohort of 216 index cases with AF as well as 600 unrelated healthy subjects, and a new TBX20 mutation, NM_001077653.2: c.862G>C; p.(Asp288His), was found to co-segregate with AF in Family 2. The gene discussed is TBX20; the disease is atrial fibrillation.