SNX27 and Hydrocephalus: In addition, SNX27 knockout is reported to lead to ciliogenesis defect in ependymal cells and hydrocephalus; however, the role of SNX27 in ependymal ciliogenesis appears to be indirect: SNX27 deficiency results in over-activation of Notch signaling and suppression of ependymal cell differentiation, which leads to decreased ependymal cell number and concomitant reduced cilium number [19].