Several neurological disorders including multiple epilepsy subtypes, neuropathic pain, and schizophrenia, as well as various insults such as trauma and ischemia, are associated with significant decreases in the Cl− extrusion capacity of KCC2 that result in increases of [Cl−]i and the subsequent hyperexcitability of neuronal networks. This evidence concerns the gene SLC12A5 and nervous system disorder.