MARBLE BONE DISEASE

also called osteopetrosis rare recessive hereditary abnormality in which the bones become extremely dense, hard, and brittle. The disease progresses as long as bone growth continues: the marrow cavities become filled with compact bone, and severe anemia results. Fractures are frequent; deafness and loss of vision may occur because cranial nerves become compressed by the narrowing of their passageways as bone is deposited in the skull. Severe cases may be fatal; mild cases do not impair a normal life expectancy.