NHERF1-deficient mice develop hydrocephalus. A-B. Comparison between 5-week-old NHERF1(+/+) and (−/−) littermates showing smaller size and bossed skull (arrow) (A) and severely distended 3rd (3V) and lateral ventricles (LV) with compression of the brain, resulting in a thin nutshell appearance of the cerebral hemispheres (B) in the NHERF1(−/−) littermate. C. Immunoflourescence analysis of 5-week-old NHERF1(+/+) mice and their NHERF1(−/−) littermates with subclinical mild hydrocephalus shows NHERF1 labeling of the apical PM in NHERF1(+/+) ependyma and β-catenin labeling of adherens junctions (arrows) in both genotypes. D. Acetylated tubulin immunofluorescence labeling of the ependymal cilia shows robust cilia tufts in NHERF1(+/+) mice and present but disorganized cilia in NHERF1(−/−) littermates with subclinical mild hydrocephalus.