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Alternative names Return to top
Brittle bone diseaseDefinition Return to top
Osteogenesis imperfecta is a congenital (present from birth) condition of abnormal fragility of the bones.Causes, incidence, and risk factors Return to top
This bone disorder is usually present at birth as an inherited disease. Osteogenesis imperfecta (OI) is classified into four major types (and further subtypes).
All four types of OI are caused by defects in the amount or structure of type 1 collagen, an important part of the bone matrix. The collagen problem usually results from a dominant genetic defect. This defect may be acquired by several different mechanisms:
Symptoms Return to top
All of the bones are abnormally weak in a person with OI. The severity of the abnormality varies enormously -- from type 2 OI, which is usually lethal in infancy (or even before birth) to type 1 OI, which may be so mild that the diagnosis is not made, even in adulthood.
The three classic symptoms of OI includes fragile bones, early hearing loss, and whites of the eyes that appear bluish (blue sclerae). Nevertheless, not all people with OI will have blue sclerae or hearing loss. All do have fragile bones, but not all people with OI will ever break a bone.
A variety of other symptoms may be found in the various types of OI:
Signs and tests Return to top
A physical examination may confirm the presence of fractures, deformities, and other symptoms.
Bone x-rays may show multiple healed fractures.
The diagnosis is made by collagen studies done on a skin punch biopsy. Once the specific molecular diagnosis is known, family members can be tested by a DNA blood test. DNA testing on prenatal chorionic villus samples (CVS) can make the diagnosis during pregnancy.
Severe OI is visible on prenatal ultrasound as early as 16 weeks.
Treatment Return to top
Fractures must be repaired quickly in the usual ways to avoid deformities. There is no specific treatment for the underlying disease. However, there are several therapies that may improve the quality of life for patients with OI:
Expectations (prognosis) Return to top
Permanent deformity of the extremities may occur. Brain damage may result from skull fractures. The disorder can be fatal. The disease is grouped by type:
Complications Return to top
Calling your health care provider Return to top
This disorder is often diagnosed at birth, but mild cases may not be detected until later in life. Call for an appointment with your health care provider if symptoms suggestive of this disorder occur.
Prevention Return to top
Genetic counseling is recommended for prospective parents if one or both are affected by this disorder.
Update Date: 7/15/2004 Updated by: John Goldenring, M.D., MPH, Department of Pediatrics, Children's Hospital, San Diego, CA. Review provided by VeriMed Healthcare Network.
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Page last updated: 28 October 2004 |