PTCH1 and keratoconus: Specifically, they are required to activate GLI-Kruppel family members, the transcriptional effector of the Hh pathway in response to ligand, leading to expression of Hh target genes, including the Hh receptor patched 1 (Ptch1) and Gli1. As KC cells have a higher propensity to undergo ADM, we explored whether this is due to an inability to respond to Hh signalling by analysing primary cilia presence and function in these cells.