PTCH1 and Hydrocephalus: Mutations in genes responsible for normal neuronal progenitor cell division, differentiation, maturation or migration, such as TRIM71, SMARCC1, PTCH1, SHH and L1CAM, or in genes encoding cell adhesion proteins important for the ependymal cell maturation and ependymal layer integrity, such as MPDZ, YAP and JAM-C, leads to hydrocephalus in humans and mice (Furey et al., 2018; Feldner et al., 2017; Tonosaki et al., 2014; Park et al., 2016).