Naz G et al. – Frizzled 6 (FZD6) belongs to a family of proteins that serve as receptors in Wnt signalling pathways, and has been shown to act as a negative regulator of the canonical Wnt/β–catenin signalling cascade and a positive regulator of the noncanonical Wnt or planar cell polarity pathway. The present results therefore suggest that FZD6 plays a pivotal role in the growth and guidance of the nail plate in humans by acting as a molecular switch between different Wnt pathways. Previous studies have identified mutations in the RSPO4 and LMX1B components of the Wnt pathway in patients with the hypoplastic nail disorders anonychia and nail–patella syndrome, respectively. Only recently, FZD6 mutations were identified in isolated nail dysplasia. The present results emphasize the important role of the Wnt pathways in nail development and increase understanding of Wnt–mediated developmental events in general. [more...]