Loss-of-function mutations in SCN5A have been associated with BrS (Chen et al., 1998; Christien Li et al., 2016; Lee et al., 2020), sick sinus syndrome (SSS) (Benson et al., 2003), progressive cardiac conduction defect (PCCD, or Lenègre-Lev disease) (Tan et al., 2001) and overlap disorders between these conditions (Remme et al., 2008). This evidence concerns the gene SCN5A and sick sinus syndrome.