Fig. 2

Main neuropathological findings in fetuses with CRB2 pathogenic variants. Macroscopic coronal section of the brain of fetus 1 showing severe bilateral ventricular dilatation, thinning of the cerebral parenchyma and undiscernible third ventricle (arrow) (A). Macroscopic transversal section of the midbrain showing atretic aqueduct of Sylvius while the pons and cerebellum appear normal (B). Hematoxylin and eosin staining of transversal sections along the mesencephalon and medulla of a control fetus (C, E, G, I, K) and fetus 3 (D, F, H, J, L) showing small dysmorphic aqueduct with multiple indentations and rosettes (D, H) with otherwise normally ciliated ependymal cells in fetus 3 (F, J) as compared to the age-matched control (C, E, G, I). Transversal section of the medulla showing atresia of the central medullar canal, reduced to 3 rosettes (L) as compared to an age-matched control in which the central canal of the medulla is normally visualized (K)