In addition to ND, the norrie disease protein gene(NDP) mutations have been reported in four otherdistinct retinopathies, namely persistent hyperplasticprimary vitreous (PHPV), XL-familial exudative vitreousretinopathy (XL-FEVR), retinopathy of prematurity(ROP) and Coats’ disease, suggesting a commonmolecular pathogenicpathway. The gene discussed is NDP; the disease is Norrie disease.