Premature craniosynostosis-a complication of thyroid replacement therapy

Three hypothyroid children with premature craniosynostosis are presented, who have been treated intensively with 1-thyroxine from early infancy. It is postulated that the craniosynostosis is the result of iatrogenic hyperthyroidism during a critical period of skull growth. Various regimens of treatment for hypothyroidism are discussed with recommendations for avoiding this potentially hazardous complication of therapy.