SPP1 and oculodentodigital dysplasia: Esseltine et al. obtained induced pluripotent stem cells (iPSCs) from a patient with a connexin‐linked ODDD and found that, compared to wild-type iPSCs, they showed reduced Cx43 mRNA and protein and impaired channel function, which translated to delayed osteoblast differentiation, along with delayed expression of collagen‐I bone sialoprotein (BSP) and osteopontin (OPN) in differentiated ODDD cells [84]. However, some mutations found in patients with ODDD can lead to reductions in gap junctions but also a hemichannel gain of function [85].