TSPAN12 and Familial exudative vitreoretinopathy: FZD4, LRP5, or TSPAN12 mutations are also the causes of a spectrum of related congenital retinopathies such as osteoporosis-pseudoglioma syndrome, familial exudative vitreoretinopathy (FEVR), and Coats disease, each of which share resembling phenotypes with Norrie disease.