Fracture patterns in two types of autosomal-dominant osteopetrosis.

Thirty-five individuals with autosomal-dominant osteopetrosis were interviewed and radiographs were reviewed. Twenty had the radiographic Type I osteopetrosis, characterized by diffuse, symmetric osteosclerosis and pronounced sclerosis of the skull with a thickened cranial vault. Fifteen had Type II, where the most striking findings were diffuse symmetric osteosclerosis, "Rugger Jersey Spine," and endobones (bone within a bone) in the pelvis, while the cranial vault was almost unaffected. Of the 12 probands who had had a fracture, 2/20 were Type I and 10/15 were Type II. Fracture complications were also more frequent in Type II.