PCDH19 and epilepsy: Mutations in protocadherin 19 (PCDH19), a protein involved in stabilization of extrasynaptic GABAARs that contribute to tonic inhibition, are also associated with another severe form of epilepsy: epileptic encephalopathy, early infantile 9 (Dibbens et al., 2008; Smith et al., 2018; Kolc et al., 2019; Serratto et al., 2020).