Osteogenesis imperfecta Health Dictionary

A congenital condition characterized by abnormally brittle bones that are unusually susceptible to fractures. The condition is caused by an inherited defect in the connective tissue that forms the basic material of bone. Severely affected infants are born with multiple fractures and a soft skull and do not usually survive. Others have many fractures during infancy and childhood, often as a result of normal handling and activities, and it may be difficult to distinguish the condition from child abuse. A common sign of the condition is that the whites of the eyes are abnormally thin, making them appear blue. Sufferers may also be deaf due to otosclerosis. Very mild cases may not be detected until adolescence or later.

There is no specific treatment. Fractures are immobilized and usually heal quickly, but they may cause shortening and deformity of the limbs, resulting in abnormal, stunted growth. Skull fractures may cause brain damage or death. Parents may have genetic counselling to estimate the risk in future children. Severe cases can be diagnosed prenatally by ultrasound scanning.

A hereditary disease due to an inherited abnormality of COLLAGEN. It is characterised by extreme fragility of the skeleton, resulting in fractures and deformities. It may be accompanied by blue sclera (the outermost, normally white coat of the eyeball), transparent teeth, hypermobility (excessive range of movement) of the joints, deafness, and dwar?sm (shortness of stature). The exact cause is not known, although there is some evidence that it may be associated with collagen formation. Parents of affected children can obtain help and advice from the Brittle Bone Society.

(OI, fragilitas ossium, brittle bone disease) a congenital disorder of connective tissue formation that affects bone, teeth, and soft tissues. It has an estimated incidence of 1 in 20,000 and there are at least eight types, of varying severity, the worst being lethal at birth. Most types are inherited as autosomal *dominant characteristics. In all types the bones are brittle and fracture easily; the *sclerae may be blue and teeth are often deformed. See also dentinogenesis (imperfecta).