Mutations in SCN5A, the gene that encodes the pore-forming subunit of human cardiac sodium channel Nav1.5, have been associated with a variety of inherited arrhythmogenic syndromes including type 3 long-QT syndrome (LQT3)4, Brugada syndrome (BrS)5, progressive cardiac conduction disease (PCCD)6, sick sinus syndrome (SSS)7, atrial fibrillation (AF)8, dilated cardiomyopathy (DCM)9 and more complex overlapping syndrome10, 11. This evidence concerns the gene SCN5A and long QT syndrome 3.