Osteogenesis imperfecta (OI) is a genetic
disorder that prevents the body from building strong bones.
People with OI might have bones that break easily, which is why the condition is
commonly called brittle bone disease.
What Causes Osteogenesis Imperfecta (OI)?
Osteogenesis imperfecta (os-tee-oh-JEN-uh-sis im-pur-FEK-tuh) happens because of
a defect in the gene that makes the protein collagen. Collagen
is an important building block of bones.
People who have OI are born with it. They either don't have enough collagen in
or have collagen that doesn't work as it should. This makes their bones weaker and
more brittle than normal bones. It can also lead to bone deformities. (Deformed bones
do not have normal shapes.)
The defect in the gene can be inherited from a parent. Kids with OI often have
a parent who has the condition. Sometimes, the defect in the gene happens spontaneously
at the time of conception.
What Are the Signs & Symptoms of Osteogenesis Imperfecta (OI)?
The severity of osteogenesis imperfecta can vary. Some people won't know they have
it until they fall and break a bone. For them, the only symptom of OI might be an
occasional broken bone. Other people can have many bone breaks without any obvious
Signs of OI include:
bones that break with no known cause or from very minor trauma
a blue, purple, or gray tint to the sclera
(the whites of the eyes)
triangular face shape
hearing loss in adulthood
What Are the Types of Osteogenesis Imperfecta (OI)?
Doctors classify the different types of OI based on how severe the condition is.
To date, 15 types of OI have been identified.
Most cases of OI have symptoms that fall into one of these four classifications:
Type I osteogenesis imperfecta — people with type I OI have
less collagen than normal. This makes their bones fragile, but they don't have bone
deformities. The first break usually happens when a child starts walking. Fractures
typically decrease after puberty.
Type II osteogenesis imperfecta — babies with type II OI
usually are born with many fractures, are very small, and have severe breathing problems.
As a result, most will not survive.
Type III osteogenesis imperfecta — people with type III
OI usually will be shorter than their peers, and may have severe bone deformities,
breathing problems (which can be life-threatening), brittle teeth, a curved spine,
ribcage deformities, and other problems.
Type IV osteogenesis imperfecta — people with type IV OI
can have mild to serious bone deformities, short stature, frequent fractures (which
may lessen after puberty), and a curved spine.
How Is Osteogenesis Imperfecta (OI) Diagnosed?
Besides a family history of OI, doctors look for frequent or unexplained bone fractures,
dental problems, blue sclera (the white part of the eye), short stature, and other
symptoms as signs that a child has OI.
They might also order tests like:
X-rays, which can show fractures or healed breaks
DNA tests, to identify the collagen gene mutation
blood tests or urine tests, usually to make sure that other conditions,
such as rickets, aren't causing the symptoms
biochemical testing, which may include a skin
sample to examine the collagen
There's no cure for osteogenesis imperfecta. Treatment is based on a child's specific
symptoms, and can include physical therapy and mobility aides, occupational
therapy, medicine, and surgery. The goal is to prevent fractures, treat them properly
when they do happen, preserve mobility and independence, and strengthen bones and
The treatment team might include a primary care doctor, an orthopedist, rehabilitation
specialists, an endocrinologist, a geneticist, a neurologist, and a pulmonologist.
Preventing Broken Bones
Preventing bone fractures is key for people with OI. They can lower their risk
of broken bones by:
avoiding activities that put them at risk for a fall or collision, or put too
much stress on the bones
doing low-impact exercises (such as swimming) to build muscle strength and mobility
and increase bone strength
When bones do break, it's important to treat them right away with casts,
splints, and braces. Orthopedists (doctors who specialize in treating bone problems)
might recommend using lightweight versions of these devices that allow some movement
Physical therapy (PT)
can be helpful for many kids with OI. It can build muscle strength, which helps maintain
function, promote aerobic fitness, and improve breathing. Kids who need them can learn
how to use mobility aides and assistive
devices. In younger kids, PT can help with motor skill development.
Doctors might prescribe bone-strengthening medicines to increase bone density and
further reduce the chances of fractures. Some people will need treatment to maintain
bone strength for the rest of their lives.
Sometimes, surgery is needed to repair a broken bone or fix a deformity. Surgeons
also might place metal rods into long bones (like the femur, tibia, and humerus) to
prevent breaks. Surgery also can correct dental problems from brittle teeth, and help
with hearing problems.
Bone breaks due to OI usually lessen in early adulthood, although they can start
happening again later in life.
Taking steps to prevent fractures — along with early, ongoing medical care
— will help most people with OI lead healthy, productive lives.