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About OI

About OI

What is Osteogenesis Imperfecta?

Osteogenesis Imperfecta (OI) is a genetic bone disorder characterised by fragile bones that break easily. It is also known as brittle bone disease. A person is born with this disorder and is affected throughout their lifetime.

OI is a disorder of collagen, a protein which forms the framework for the bone structure. In OI the collagen may be of poor quality, or there just may not be enough to support the mineral structure of the bones. This makes the bones weak and fragile and results in the bones being liable to fracture at any time, even without trauma.

OI is a rare condition and it is estimated that the number of people born with the condition is approximately 1 in every 15,000: that equates to around 5000 individuals in the UK living with OI.

What causes the condition?

OI is caused by a genetic mutation that affects the production of collagen, which can be found throughout the body, especially in a person’s bones and other tissues.  A genetic condition such as OI can be hereditary and passed on from parents to children. Around 25% of children with OI are born into a family where there is no family history of the condition. This occurs when the child has a “new” or “spontaneous” dominant mutation.

What are the symptoms?

OI exhibits wide variations in appearance and severity, so a classification system has been identified to describe the different types of OI. Severity can also be described as mild, moderate, or severe. Some people with OI hardly have any symptoms, but in others, OI may lead to physical disability requiring the use of walking sticks, walking frames and wheelchairs.

As the composition of collagen in the bone is not correct, even when there are no fractures there will be other problems connected to the condition; such as the ligaments stretch more easily, joint hypermobility can significantly affect the quality of life as it results in fatigue of many muscle groups. As a result, the mobility and performance of ordinary tasks of everyday living are impaired. Other symptoms can be; hearing loss, fatigue, joint laxity, curved bones, scoliosis, blue sclerae, dentinogenesis imperfecta (brittle teeth), and short stature amongst other medical problems.

For more information see our factsheets and films on our information and resources page.

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