This leaflet was written by Dr Suma Uday, Senior Consultant in Metabolic Bone Disease, Indian Osteogenesis Imperfecta Foundation.
What does ‘genetic’ mean in Osteogenesis Imperfecta (OI)?
Osteogenesis Imperfecta is a genetic condition, which means it is caused by changes (mutations) in the genes that control how the body makes collagen — the protein that gives strength and structure to bones. When collagen is not made properly, bones become more fragile and can break easily.
Which genes are involved in most cases of OI?
Most people with OI have a change in one of two genes — COL1A1 or COL1A2. These genes give instructions for making type I collagen, the main building block of bone. There are also several other, rarer genes that can cause OI. Scientists have now identified over 20 genes related to OI, which can affect collagen or other proteins that help bones stay strong.
How is OI passed on (inherited)?
There are a few different ways OI can be passed from parents to children:
- Dominant inheritance: One changed gene from either parent is enough to cause OI. This is the most common pattern. Recessive inheritance: Both parents carry one changed gene each but do not have OI themselves. Their child can develop OI if they inherit both copies of the changed gene. New (spontaneous) mutation: Sometimes, the gene change happens for the first time in a child. This means there may be no family history of OI
Can OI happen even if no one else in the family has it?
Yes. Many children with OI are the first in their family to have the condition. This happens when the gene change occurs by chance during early development.
Why do symptoms vary so much between people with OI?
The type of gene change and where it happens can affect how much collagen is made and how strong it is. Even within the same family, two people with OI can have different numbers of fractures or different physical features.
Can genetic testing help?
Yes. A genetic test can:
- Confirm the diagnosis of OI
- Identify the exact gene causing it
- Help doctors give accurate advice about inheritance and treatment
- Support planning for future pregnancies or family screening Your doctor or genetic counsellor can guide you on when and how testing is useful.
Should parents or siblings be tested?
Sometimes yes — especially when the type of inheritance is not clear, or when parents plan for more children. Testing can help families understand the chances of passing on OI. Always talk to your doctor or local expert before testing.
Are new genes and treatments still being discovered?
Yes. Research continues to find new genes and improve treatments. Scientists are also studying how these genes work to create safer and more effective therapies in the future.
Where can I learn more?
Families in India can find reliable information, guidance, and community support through the Indian Osteogenesis Imperfecta Foundation (IOIF) — the national organisation dedicated to people living with OI. There are also international societies where more information and resources are available:
- Brittle Bone Society (BBS) — United Kingdom
- Osteogenesis Imperfecta Federation Europe (OIFE) — Europe
- Osteogenesis Imperfecta Foundation (OIF) — United States
For more information about genetic testing or support, consult your local expert or OI specialist team.
About the Indian Osteogenesis Imperfecta Foundation (IOIF)
The Indian OI Foundation works to support families, raise awareness, and improve access to expert care for people living with Osteogenesis Imperfecta in India. Visit our website or contact your local OI specialist for more information and family resources.