Forever Young

Mutations in the α subunit of the cardiac sodium channel, encoded by SCN5A , have been identified in a broad range of cardiac rhythm disorders that include long QT3 (LQT3), Brugada syndrome, progressive cardiac conduction disease, sick sinus syndrome, atrial fibrillation, and dilated cardiomyopathy. Since the identification of the first SCN5A mutation in long QT syndrome in 1995, more than 200 mutations have now been reported.1 Initially, it was assumed that each arrhythmic phenotype was attributable to a specific SCN5A mutation; however, "overlap syndromes", where single individuals exhibit clinical features of Brugada syndrome and LQT3, are now well characterized.2 The broad phenotypic range of SCN5A mutations underscores the importance of tight sodium channel regulation in maintaining normal rhythmicity. (SELECT FULL TEXT TO CONTINUE)