Osteogenesis imperfecta (OI) is a genetic disorder that causes a person's bones to break easily, often from little or no apparent trauma. OI is also called "brittle bone disease."
It varies in severity from person to person, ranging from a mild type to a severe type that causes death before or shortly after birth. In addition to having fractures, people with OI also have teeth problems (dentinogenesis imperfecta), and hearing loss when they are adults. People who have OI may also have muscle weakness, loose joints (joint laxity) and skeletal malformations.