For example, Rnd3 interacts preferentially with plexin‐B2 of the three plexin‐B proteins to induce cell rounding,19 whereas Rnd3 regulates Notch signalling in the ependymal epithelium, resulting in hydrocephalus through epithelial overgrowth in RND3 null mice.20 This evidence concerns the gene RND3 and Hydrocephalus.