While the inactivation of several of the potassium channels like Kv1.2, Kv1.1, and Kcnj10 (Kir4.1) are important for neuronal excitability, action potential width, and firing properties, in general, mutations in the genes encoding these channels that alter their inactivation are known to lead to temporal lobe epilepsy (Shen et al., 2004; Kaczmarek, 2006; Schulte et al., 2006). The gene discussed is KCNA1; the disease is temporal lobe epilepsy.