A direct association between KCC2 dysfunction and numerous psychiatric or neurological disorders (Kahle et al., 2008; Kaila et al., 2014), including epilepsy (Di Cristo et al., 2018), Huntington’s disease (Dargaei et al., 2018), schizophrenia (Hyde et al., 2011), and Rett syndrome (Tang et al., 2016), has been reported. The gene discussed is SLC12A5; the disease is epilepsy.