Neonatal Hyperthyroidism with Accelerated Skeletal Maturation, Craniosynostosis, and Brachydactyly

Case reports of two premature siblings with hyperthyroidism are presented. Each child showed markedly advanced bone age at birth. Craniosynostosis, brachydactyly, and coneshaped epiphyses developed in both cases. Bone age was in advance of chronological age until age four and a half and age eight, respectively. Two entities, peripheral dysostosis and pseudohypoparathyroidism, show radiographic findings similar to those seen in the cases reported. Differential diagnosis is discussed. Since the neonatal hyperthyroid state may have caused the abnormalities observed in these cases, hyperthyroidism should be included as a possible causal factor in craniosynostosis and brachydactyly.