Other SCN5A-mediated conditions such as familial atrial fibrillation [10], sudden infant death syndrome [11], familial dilated cardiomyopathy (DCM) [8,12], and, rarely, arrhythmogenic right ventricular cardiomyopathy (ARVC) [13], have a more complex pathophysiology with involvement of multiple molecular phenotypes. The gene discussed is SCN5A; the disease is arrhythmogenic right ventricular cardiomyopathy.