IHH and enthesopathy: Taken together with our data showing that 1,25D prevents enthesopathy in Hyp (14) and C–/– mice with early initiation of therapy, these studies demonstrate that 1,25D prevents differentiation of normal enthesis cells into HECs, but 1,25D is unable to attenuate BMP and IHH signaling after differentiation into HECs has occurred and enthesopathy has developed.