Mutations in SCN5A are a major cause of AV block, sick sinus syndrome, progressive CCD, and eventual DCM leading to sudden death (Amin et al., 2010; Chockalingam et al., 2012; Holst et al., 2010; Lee et al., 2016; Makita, 2009; Samani, Ai, et al., 2009; Samani, Wu, et al., 2009; Shuraih et al., 2007). The gene discussed is SCN5A; the disease is atrioventricular block.