INVS and normal pressure hydrocephalus: Proteins from the InvsC disrupted in infantile NPH including INVS/NPHP2 and NPHP3 have been proposed to be required for the switch from canonical Wnt signaling, involved in cell proliferation, to non-canonical Wnt signaling which maintains planar cell polarity, although the precise role in cystogenesis is debated (Simons et al., 2005; Bergmann et al., 2008; Sugiyama et al., 2011; Wang et al., 2018).