KCNQ1 and KCNQ4 are expressed in multiple tissues (KCNQ4 in the auditory system and vasculature, KCNQ1 in the cardiovascular system and multiple epithelia) and their activation might cause unwanted off-target effects if one were instead intending to target KCNQ2 in epilepsy, for example. This evidence concerns the gene KCNQ4 and epilepsy.