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About OI

About OI

What is Osteogenesis Imperfecta?

Osteogenesis Imperfecta (OI) is a genetic condition present from birth. Its most striking feature is that fractures may occur easily. Therefore it is frequently called “brittle bone disease”.

Description of OI

OI is a disorder of collagen, a protein which forms the framework for the bone structure as well as other parts of the body. In OI the collagen may be of poor quality, or there may just 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.

How many people have OI?

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 may be other problems connected to the condition such as:
– bone fragility
– short stature (but people can also have normal height)
scoliosis and other skeletal deformities
– loose joints (hypermobility)
– fatigue
– blue sclerae
hearing impairment
dentinogenesis imperfecta

For more information about OI see our full list of factsheets and films .  

See our Support section for further information.