Mutations in the NDP gene and the receptor genes, FZ4, LRP5, and TSPAN-12, have been identified for vitreoretinal diseases including Norrie Disease, Familial Exudative Vitreoretinopathy, and Coats' Disease (Nikopoulos et al., 2010; Ye et al., 2010; Ohlmann and Tamm, 2012). Here, NDP is linked to Norrie disease.