Frizzled-6

Structurally typical of the family yet functionally distinctive, Frizzled-6 (FZD6) operates mainly through non-canonical planar cell polarity signaling to orient cells within the epithelial plane. Mouse studies established it as a master regulator of hair patterning: Fzd6-knockout animals lose the whorled arrangement of trunk hair and display reversed hair orientation on the back. In humans, FZD6 mutations cause an autosomal recessive nail dysplasia with thickened, claw-shaped nails, confirming its role in appendage morphogenesis. The receptor is widely expressed in adult tissues including lung and kidney and responds to ligands such as Wnt5a and Wnt7b. Its planar-cell-polarity-selective signaling makes FZD6 a valuable tool for studying tissue polarity and a potential target in fibrotic and oncological settings.