Craniosynostosis can be gene-linked, or caused by metabolic diseases, such as rickets, which results from a deficiency or impaired metabolism of vitamin D, magnesium, phosphorus or calcium leading to hypomineralization of the bone. X-linked dominant hypophosphatemic rickets (XLHR) is the most prevalent genetic type of hypophosphatemic rickets and is caused by germ line mutations in the PHEX-gene. In XLHR, only few case reports of craniosynostosis were described.