NDP and Familial exudative vitreoretinopathy: In addition to those environmental factors, genetic mutations are also considered to get involved in ROP development, especially Wnt signaling factors: Frizzled-4 (FZD4), Tetraspanin-12 (TSPAN12), and Norrin (NDP), this signaling system plays and important role in fetal vascular formation of retina and inner ear [10, 11], and its functional disruption could be associated with the pathogenesis of some retinal vascular disorders like Coat’s disease and familial exudative vitreoretinopathy (FEVR) [12, 13].