Since VEGF is a factor which triggers a breakdown of the blood-retinal barrier (e.g., in neovascular AMD and diabetic retinopathy) [20], the data may suggest that VEGF induces a downregulation of Kir4.2 in RPE cells via two mechanisms: by a direct VEGF receptor-mediated effect and by an indirect effect through the breakdown of the blood-retinal barrier which permits a flux of blood constituents into the retina. Here, KCNJ15 is linked to diabetic retinopathy.