Craniosynostosis in vitamin D-resistant rickets

Abstract

✓ Craniosynostosis and associated craniofacial deformities, such as frontal bossing, often occur as symptoms of vitamin D-resistant rickets in children. Similar skull deformities develop in mice with X-linked dominant hypophosphatemia, the most common form of vitamin D-resistant rickets. These mice have a short, wide, high neurocranium, which suggested an inhibition of coronal suture growth. To study this question, we compared histologically the postnatal development of the coronal sutures in normal and hypophosphatemic mice between 1 and 13 weeks of age. Premature fusion of the coronal suture occurred in hypophosphatemic mice by 4 weeks of age. The proportion of the suture obliterated by bone varied among individual animals, but craniosynostosis was present in all animals studied at 4 weeks and older. Fusion of the coronal suture did not occur through 13 weeks of age in any of the normal mice studied. The X-linked hypophosphatemic mouse is an animal model that can be used to study the role of vitamin Dresistant rickets in the development of craniosynostosis, to relate craniosynostosis to the development of associated skull deformities, and to test new treatment procedures.