The role of the cardiac sodium channel in perinatal early infant mortality

The cardiac sodium channel gene, SCN5A, plays an important role in arrhythmias of genetic origin. With exceptions, loss-of-function mutations become more important in adult life, whereas gain-of-function mutations can manifest their clinical impact very early, also in the perinatal period. The best-known disease caused by the latter variants is long QT syndrome type 3, which tends to manifest in adolescence. However, when symptoms appear in the first year of life the likelihood of cardiac arrest and sudden death is very high.