A 2007 consensus report by the U.S. National Heart, Lung, and Blood Institute and the Office of Rare Diseases on gene mutations affecting ion channel function concluded that genetic testing for LQTS must be combined with clinical evaluation, and noted lack of clarity in the proportion of SQTS cases that might be explained by the corresponding KCNH2, KCNJ2, and KCNQ1 genes45. Here, KCNH2 is linked to familial long QT syndrome.