Perturbations in cytokine signaling affect bone remodeling due to a defect in osteoclast differentiation; for example, biallelic loss-of-function variants in the interleukin 11 (IL-11) co-receptor, IL11RA, cause craniosynostosis, possibly owing to an osteoclast defect and subsequent failure to break down the bone matrix. The gene discussed is IL11; the disease is craniosynostosis.