The KCNQ2 gene encodes alpha-subunits of the potassium voltage-gated Kv7.2 channels, which are present in higher numbers at axonal initial segments and at nodes of Ranvier in the central nervous system. These channels transport potassium ions out of cells and in thus doing; they transmit a particular type of electrical signal called the M-current. The latter plays a key role in determining the subthreshold of electroexcitability of neurons as well as the responsiveness to synaptic inputs. Therefore, it ensures that the neuron is not constantly active, or excitable.