Osteogenesis Imperfecta (OI) is a genetic disorder that affects the production of a protein called collagen. Collagen is one of the main proteins in bone and is what gives bone its strength.
Symptoms of OI
Children born with OI may suffer fractures while still in the womb, during delivery, or they may suffer their first fracture soon after birth. Fractures of bones may occur with normal handling. Fractures may not be identified right away, and are sometimes discovered later in the child's life when x-rays are done for a different reason.
Fractures in OI are unpredictable. For example, fractures that might be expected to occur from an injury often don't, and fractures that do occur can happen under the mildest of circumstances. The good news is that rates of fractures often decrease with age.
There are other signs and symptoms that doctors may look for that also may occur as a result of the collagen defect in OI:
- Lax (loose) joints and muscle weakness
- Blue or grey discoloration of the white part of the eye (sclera)
- Teeth that break easily and may be discoloured
- A tendency towards bruising
- Heat intolerance and excessive sweating
- Scoliosis (curvature of the spine) and other curved bones
- Breathing issues (in severe cases)
- Deafness or hearing loss
How OI happens
OI can be passed down in families from one generation to the next in a recessive fashion. This means that only one parent needs to carry the gene in order for OI to be passed to their children. Often OI is the result of a new genetic mutation; in other words, it just "happens". This is true in about 35% of cases.
How OI is diagnosed
Mild OI often goes undetected and undiagnosed. When OI is suspected, usually because of a history of frequent fractures, physicians look for other associated symptoms such as those mentioned previously. The child may be seen by a geneticist or a doctor knowledgeable in diagnosing OI. Blood tests and skin biopsies can now be done to assure the diagnosis. Some patients with OI have extra small bones in their skull along suture lines, where the different sections of the skull come together. These bones are called wormian bones, and can help make the diagnosis of OI.
How OI is treated
At present, there is no cure for OI. Treatment of OI is symptomatic and supportive. Fractures, if they occur, should be monitored carefully to ensure proper healing. Surgery is sometimes done to stabilize bones. Occupational therapy can be used to teach parents how to handle their child so as not to injure them inadvertently. Children with OI may be prescribed braces to support their limbs as needed. Hearing should be monitored frequently in children diagnosed with OI, as deafness and hearing loss can occur if small bones in the middle ear break. Medications to strengthen bones may be prescribed.
Advances in knowledge of OI allow children with OI to lead fuller lives. Prompt diagnosis is important, as the earlier children are diagnosed, the sooner measures to protect them from fractures can begin. If you suspect your child may have OI, see your physician.