Mechanosensory proteins polycystic kidney disease 1 (Pkd1) and Pkd2 are expressed in primary cilia of RGCs, and their ablation leads to postnatal hydrocephalus and planar cell polarity defects in mouse ventricular epithelium (Wodarczyk et al., 2009; Ohata et al., 2015). Here, PKD2 is linked to Hydrocephalus.