SCN5A and familial long QT syndrome: nsSNPs in KCNQ1 (KV7.1 channel protein, which complexes with the protein KCNE1 to generate the slow cardiac potassium repolarization current, IKs) and SCN5A (NaV1.5 channel protein, which generates the cardiac depolarizing sodium current, INa), are associated with heritable diseases of the heart [4,36,37,38,49] including dilated cardiomyopathy [14,28], cardiac conduction disease [6,29], short QT syndrome [13], sick sinus syndrome [15], types 1 and 3 congenital long QT syndromes (LQTS) [7,18,30,38], and Brugada syndrome (BrS) [5].