Many genes are implicated in several phenotypes including SCN5a that encodes for the α1-subunit for the cardiac sodium channel (Brugada syndrome, cardiac conduction disease, and LQTS), RYR2 (CPVT and CRDS), and hERG1 (LQTS and SQTS), which highlights the need for functional characterization combined with deep clinical phenotype assessment. Here, KCNH2 is linked to familial long QT syndrome.