SCN5A and sick sinus syndrome: Loss-of-function mutations in the cardiac sodium channel gene SCN5A are associated with BrS (Kapplinger et al, 2010), PCCD (3), DCM in combination with atrial and ventricular arrhythmias and conduction disease (McNair et al, 2004), sick sinus syndrome (SSS) (Benson et al, 2003), familial atrial fibrillation (AF) (Darbar et al, 2008), and sudden cardiac infant death syndrome (SIDS) (Klaver et al, 2011).