SCN5A and Brugada syndrome: The p.His558Arg is a common variant in humans that was already established as a modifier of the SCN5A-associated phenotypes namely the Brugada syndrome (Marangoni et al., 2011; Núñez et al., 2013; Poelzing et al., 2006; Viswanathan, Benson & Balser, 2003), familial sick sinus syndrome (SSS) (Gui et al., 2010) and Long QT syndrome (Shinlapawittayatorn et al., 2011; Vatta et al., 2021).