Immunostaining for claudin‐5 (a component of endothelial cell tight junctions previously reported as a marker of the abnormal vasculature in Norrie disease; Bryant et al, 2022) showed low/absent claudin‐5 in most of the Ndp‐KO blood vessels of the stria vascularis and spiral ligament compared to WT (Fig 6K–P, white arrows). This evidence concerns the gene NDP and Norrie disease.