Summary
The name osteopetrosis includes various inherited bone disorders characterized by a generalized skeletal densification due to a defective osteoclastic resorption. Dominant osteopetrosis type I is one of the 4 types of human oteopetrosis that have been clearly identified. It is extremely rare, as only 3 families have been reported (33 cases). Clinical signs include chronic bone pain and disorders of the cranial nerves (trigeminal neuralgia, facial palsy, hearing loss), but risk of fracture is not increased. Twenty to fourty percent of the cases are asymptomatic. Radiographs show a diffuse skeletal sclerosis, thickened corticals in long bones, and a thickening of the cranial vault. Bone mineral density (lumbar spine, femoral neck) have a Z-score ranging from +4 to +8 SD. Biological and histomorphometric investigations show defective bone resorption. In case of doubt, standard radiographs of the skull, bone densitometry and familial investigations are recommended. Treatment is symptomatic. *Author: O. Benichou, M.D. (Sept. 2000)*
