OBJECTIVE This study examines a series of patients with hypophosphatemic rickets 
and craniosynostosis to characterize the clinical course and associated 
craniofacial anomalies. METHODS A 20-year retrospective review identified 
patients with hypophosphatemic rickets and secondary craniosynostosis at 3 major 
craniofacial centers. Parameters examined included sex, age at diagnosis of head 
shape anomaly, affected sutures, etiology of rickets, presenting symptoms, 
number and type of surgical interventions, and associated diagnoses. A review of 
the literature was performed to optimize treatment recommendations. RESULTS Ten 
patients were identified (8 males, 2 females). Age at presentation ranged from 1 
to 9 years. The most commonly affected suture was the sagittal (6/10 patients). 
Etiologies included antacid-induced rickets, autosomal dominant hypophosphatemic 
rickets, and X-linked hypophosphatemic (XLH) rickets. Nine patients had 
undergone at least 1 cranial vault remodeling (CVR) surgery. Three patients 
underwent subsequent surgeries in later years. Four patients underwent formal 
intracranial pressure (ICP) monitoring, 3 of which revealed elevated ICP. Three 
patients were diagnosed with a Chiari Type I malformation. CONCLUSIONS Secondary 
craniosynostosis develops postnatally due to metabolic or mechanical factors. 
The most common metabolic cause is hypophosphatemic rickets, which has a variety 
of etiologies. Head shape changes occur later and with a more heterogeneous 
presentation compared with that of primary craniosynostosis. CVR may be required 
to prevent or relieve elevated ICP and abnormalities of the cranial vault. 
Children with hypophosphatemic rickets who develop head shape abnormalities 
should be promptly referred to a craniofacial specialist.