RFX4 and Hydrocephalus: In the control mice, cilia were present in cells lining the lateral and third ventricles (Fig 2D, upper 3 images), but, in the Rfx4+/- mice with hydrocephalus, cilia were apparently detached in some areas from the cells lining the walls of the ventricles, or they were patchy or missing in some areas (Fig 2D, lower 5 images).