Type II autosomal dominant osteopetrosis

Two principal types of osteopetrosis have been distinguished. One is the dominantly inherited, relatively benign condition which is often detected radiologically in asymptomatic adults. A second type is the recessive, lethal, malignant form. Autosomal dominant osteopetrosis (ADO) has two distinct radiological subtypes known as types I and II. We report here a 23-year-old patient with ADO type II. Radiographic investigations of a skeletal survey showed generalised osteosclerosis with thickened cortex. Magnetic resonance imaging (MRI) scan disclosed osteosclerosis in superior and inferior portions of the vertebral bodies which produced a 'sandwich' appearance. The 'bone-within-bone' appearance was seen in the ileum of the patient. The vertebral bone density was found markedly elevated. The carbonic anhydrase II level was found to be normal. We discuss here the genetic etiology of this disorder.