The increased availability of mouse models of human genetic ciliary diseases has led to advances in our understanding of the diverse cellular roles played by cilia. The family of so-called “ciliopathies” includes Alstr�m Syndrome, Bardet–Biedl Syndrome, Primary Ciliary Dyskinesia, and Polycystic Kidney Disease, among many others. In mouse models of Alstr�m Syndrome and Bardet–Biedl Syndrome, we have shown developmental defects in the mechano-sensory stereociliary bundles on the apical surfaces of “hair” cells in the cochlea, the mammalian hearing organ. Stereocilia are specialized actin-based microvilli, whose characteristic patterning is thought to be dependent on the hair cell’s primary cilium (“kinocilium”). Ciliopathy-associated proteins are localized to the ciliary axoneme and/or the ciliary basal body, or to the bundle itself. Ciliopathy-associated genes functionally interact with genes of the noncanonical Wnt pathway, and so implicate PCP in the control of hair cell development.
