KCNH2 and familial long QT syndrome: In addition to the A561 site, hERG K+ channels with other LQTS-related mutations such as I31S, G601S, and S818L were found to exhibit enhanced function after treatment with 3 μM Prostratin or 2 μM IDB, while the channels with T65P, N470D were not affected by the drug administration (Fig. 3i).