Osteopetrosis

A very rare inherited disorder in which bones harden and become denser. Deficiency of one of the 2 types of bone cell responsible for healthy bone growth results in a disruption of normal bone structure. In its mildest form, there may be no symptoms; more severe forms of osteopetrosis result in abnormally high susceptibility to fractures; stunted growth; deformity; and anaemia. Pressure on nerves may cause blindness, deafness, and facial paralysis. Most treatments for osteopetrosis aim to reduce the severity of symptoms. Bone marrow transplants of cells from which healthy bone cells might develop are undertaken in some cases.