PCDH19 and Intellectual disability: Mutations in PCDH19 cause an X-linked, female-limited form of infant-onset epilepsy (PCDH19 female epilepsy, PCDH19-FE; OMIM 300088) that is associated with intellectual disability, as well as compulsive or aggressive behavior and autistic features (Dibbens et al., 2008; Scheffer et al., 2008; Depienne and LeGuern, 2012; van Harssel et al., 2013; Leonardi et al., 2014; Thiffault et al., 2016; Terracciano et al., 2016; Walters et al., 2014).