Our laboratory has previously described the PPCD1 mouse, which reproduces a hallmark feature of human PPCD, corneal endothelial metaplasia characterized by proliferation of corneal endothelial cells with epithelial features including ectopic pan-cytokeratin expression (cytokeratin AE1/AE3) [20]. The gene discussed is VSX1; the disease is posterior polymorphous corneal dystrophy.