KCNQ3 and Myokymia: This links SCA19/22 to other neurological potassium channelopathies where an alteration of the gating properties of voltage-gated potassium channels is caused by alterations of positive residues in their voltage-sensor domains [19], e.g. KCNQ2 in peripheral nerve hyperexcitability with myokymia [26], KCNQ2/KCNQ3 in benign familial neonatal convulsions [16, 17, 27] and KCNQ2 in epileptic encephalopathy [19].