For instance, mutations in Cav1.2 channels in Timothy syndrome (Splawski et al., 2004), sodium leak channel mutations in Freeman-Sheldon syndrome (Chong et al., 2015) and mutations in voltage gated potassium channel KCNH1 (Kv10.1) in Temple-Baraitser syndrome (Simons et al., 2015) are examples of channelopathies due to mis-regulated ion channels. Here, KCNH1 is linked to Freeman-Sheldon syndrome.