Osteopetrosis in children: a report of 26 cases.

We have observed 26 cases of osteopetrosis among 165,594 children hospitalized over a period of 10 years in the National Children's Hospital. The hospital serves Costa Rica, a country of nearly 2,000,000 inhabitants with 60,000 live births per year. All patients had characteristic roentgenographic bony changes. Among the early manifestations of the disease, nasal obstruction and an adenoidal expression were common. The facial appearance of the patient is characteristic. Serious complications of the disease are hematologic and neurologic disorders.