Previous studies have demonstrated that NDP, FZD4, LRP5 and TSPAN12 responsible for FEVR are in the NORRIN/β-catenin signalling pathway and that the FEVR disease is caused by mutations of components in this pathway and ZNF40819, 23, 24, 25. This evidence concerns the gene FZD4 and Familial exudative vitreoretinopathy.