In humans, mutations in PCDH19 are the causative basis of one form of epilepsy (Dibbens et al., 2008), and other δ-Pcdhs are implicated in various neurological disorders (Chang et al., 2018; Consortium on Complex Epilepsies, 2014; Morrow et al., 2008). Here, PCDH19 is linked to epilepsy.