sentences:  These include the canonical Wnt/β-catenin pathway, Wnt/calcium pathway, and planar cell polarity (PCP) pathway.Mutations in the human frizzled-4 receptor have been linked to familial exudative vitreoretinopathy, a rare disease affecting the retina at the back of the eye, and the vitreous, the clear fluid inside the eye.The frizzled (fz) locus of Drosophila coordinates the cytoskeletons of epidermal cells, producing a parallel array of cuticular hairs and bristles.