The Ulk4tm1a/tm1a hydrocephalus is congenital. A, C, H&E-stained brain sections of P0 WT mice. B, D, H&E-stained brain sections of Ulk4tm1a/tm1a mice. E, F, The relative size of LV (E) and 3V (F) at the SCO position were quantified. *p < 0.05, **p < 0.01. Scale bars: A, B, 1 mm; C, D, 50 μm. 3V, third ventricle; LV, lateral ventricle; pc, Posterior commissure; SCO, subcommisural organ; +/+, Ulk4+/+; −/−, Ulk4 tm1a/tm1a.