Sudden infant death syndrome: how significant are the cardiac channelopathies?

Having an apparently healthy, thriving infant fail to reach his/her first birthday is profoundly tragic. This tragedy is compounded when the infant's death is unexpected and unexplained, signed out as sudden infant death syndrome (SIDS). Despite impressive success and welcome reductions in these tragic deaths due in large measure to "Back-to-Sleep" campaigns, the fundamental pathogenic mechanisms precipitating such deaths remain dimly exposed. Here, we review the causal link between SIDS and mutations involving the SCN5A-encoded cardiac sodium channel, provide new findings following extensive postmortem genetic testing of long QT syndrome (LQTS)-associated potassium channel genes in a population-based cohort of SIDS, and summarize the current understanding regarding the spectrum and prevalence of cardiac channelopathies in the pathogenesis of SIDS.