Familial sick sinus syndrome possibly associated with novel SCN5A mutation diagnosed in pregnancy

Sick sinus syndrome (SSS) denotes a collection of cardiac arrhythmias associated with dysfunction of the sinoatrial node that commonly lead to disorders in cardiac rhythm and conduction.1 Mechanisms underlying the pathogenesis for sinus node dysfunction in SSS patients are still not clear. It could occur in healthy people without any evident structural heart disease. Recent studies have identified several gene mutations, including the SCN5A gene, in congenital SSS patients.2,3 SCN5A is the cardiac Na channel gene responsible for the generation and rapid propagation of action potentials in the heart.