FGF23 and hypophosphatemia: Areas for further research include understanding the true incidence of craniosynostosis in XLH, differentiating the role of hypophosphatemia and FGF23 on development of craniosynostosis, exploring the effect of medical therapy on the development and natural history of craniosynostosis in XLH, and evaluating the impact of craniosynostosis on patient QoL, psychological well‐being, and physical and cognitive development.