FOXJ1 and Hydrocephalus: We examined the cerebral ventricles of Foxj1WT/CreERT2::GFP mice (n = 3) using T2-weighted magnetic resonance imaging (MRI) and found that the ventricular volume was moderately (but significantly) enlarged when compared to the ventricular volume of Foxj1WT/WT mice (n = 3, Fig. 2c), suggesting that heterozygous Foxj1 deletion leads to Foxj1 haploinsufficiency and hydrocephalus in mice.