Frizzled-4 (FZD4) is also known as FzE4, CD344, which belongs to the G-protein coupled receptor Fz/Smo family. Most of frizzled receptors are coupled to the beta-catenin canonical signaling pathway, which leads to the activation of disheveled proteins, inhibition of GSK-3 kinase, nuclear accumulation of beta-catenin and activation of Wnt target genes.Familial exudative vitreoretinopathy (FEVR) is a hereditary blinding disorder that features defects in retinal vascular development. Mutations in FZD4 are known to cause autosomal dominant exudative vitreoretinopathy (EVR1). The mutations in FZD4 are associated with the phenotypes of retinal folds or ectopic macula in FEVR.