KCNJ2 and Andersen-Tawil syndrome: It is also worth to note that some of these channelopathies can affect different organs; for instance, LQT7 syndrome caused by KCNJ2 mutations corresponds to Andersen-Tawil syndrome, which is characterized by a triad of ventricular arrhythmias, periodic paralysis, and dysmorphic features (see above).