What is osteogenesis imperfecta (OI)?

Osteogenesis imperfecta (OI) is a genetic disorder that affects the bones. This disease causes bones to be very weak and break with little or no trauma. OI is also known as brittle bone disease. People with OI also have weak muscles and bone deformities. In order to understand OI, it is important to know the different types. There are eight different types of OI. Each type has different signs and symptoms. There are four main types and four lesser-known types. Only the four main types will be discussed. The four lesser-known types only affect a total of 10 percent of people with OI.

What are the four main types of OI?

Type I

  • Least severe and most common
  • More fractures during childhood than adulthood
  • Some children may experience hearing loss

Type II

  • More severe
  • Underdeveloped bones at birth
  • Infants are born with soft skull bones

Type III

  • Very severe
  • Many infants are born with broken bones
  • Poor muscle development
  • Curved spine
  • Treatment needed throughout life

Type IV

  • Can range from mild to severe
  • Most children experience most fractures before puberty
  • Shorter than average
  • Bowed legs and curved spine

Symptoms and Causes

What causes OI?

The cause of this mutation (change in a gene) is unknown and needs to be researched further.

What are the symptoms of OI?

OI symptoms can range based on the severity of the disease. The most common symptoms are:

  • Weak muscles
  • Malformed bones
  • Loose joints
  • Blue or purple sclera (whites of the eyes)
  • Problems breathing
  • Brittle teeth
  • Triangular face
  • Bowed legs
  • Curved spine

Diagnosis and Tests

How is OI diagnosed?

  • Physical exam by a doctor
  • Collagen test
  • Family history
  • X-rays

Management and Treatment

How OI treated?

There are many forms of treatments for the different types of OI. There is no cure for this disease, but the symptoms can be managed. Surgery to treat OI can involve the placement of rods into the bones to strengthen them and prevent them from breaking and deforming. Physical therapy can also be used to strengthen muscles and to teach patients how to prevent breaks. It is most important to practice a healthy lifestyle when one has OI. By eating a healthy diet rich in calcium, one can help improve bone strength. Doctors may also recommend certain forms of exercise to strengthen bones, maintain a healthy weight, and strengthen muscles.


Can OI be prevented?

Because OI is a genetic disease, it cannot be prevented. It is important for the doctor of any expectant parents to know of the risk of OI for the infant.

Outlook / Prognosis

What is the outlook for people with OI?

The outlook for people with OI varies greatly for each type of the disease. Most children born with type I OI live normal, healthy lives into adulthood. Less severe symptoms do not affect life expectancy. Most OI-related deaths result from respiratory failure due to weak lungs. The most severe types will result in death at birth or soon after.



Last reviewed by a Cleveland Clinic medical professional on 07/06/2015.

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