CLDN7 and chronic kidney disease: Down-regulation of TJ proteins is also observed in other pathologies involving epithelial barrier defects such as in chronic kidney disease, which is characterized by a marked depletion of TJ proteins (Claudin1, Occludin, and ZO1) in the gastric epithelium (Vaziri et al., 2013) or Kawasaki disease (KWD) where decreased ZO1 levels are associated with intestinal barrier dysfunction (Lai et al., 2020).