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Scenes like this occur in emergency rooms every day. But in this case, the cause - page 4 / 5





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blue sclera; translucent, opalescent, or discolored teeth (even in unerupted teeth in babies); a triangular shaped face; barrel-shaped rib cage; easy bruising; thin skin; excessive sweating; and other features.

Some signs such as dentinogenesis imperfecta, hearing loss, bone deformity and short stature are age-dependent and may not be evident in an infant. In its mildest form, OI may exhibit only as unexplained bone fractures in childhood.

OI remains primarily a clinical diagnosis. Generally, clinical geneticists are familiar with OI diagnosis. They have available to them biochemical (collagen) and molecular (DNA) tests that can help confirm a diagnosis of OI in some situations. A skin biopsy can be analyzed to determine if the quantity or quality of type 1 collagen is abnormal. This approach identifies almost 90% of persons known to have OI. A DNA test can be done on a blood sample to try to locate the mutations that cause OI. Several hundred mutations have been identified. This test identifies about 90% of people with OI. A few individuals test positive for OI on one test and not the other. Approximately 10% of individuals with mild or moderate OI test negative for OI through collagen or DNA testing, despite having the disorder.

that explains the injuries (Wardinsky). Besides OI, other conditions that feature fragile bones and bruising include Ehlers-Danlos syndrome, glutaric acidaemia type 1, hypophosphatasia, disorders of vitamin D metabolism, disorders of copper metabolism such as Menkes syndrome, and premature birth (Marlowe).

OI is

normally associated with calcium or phosphate deficiency, so it cannot be

diagnosed by measuring the levels of these substances in the blood.

The national Osteogenesis Imperfecta Foundation maintains a list of orthopedists and geneticists who are reputed to have experience with all types of OI. Foundation staff can suggest appropriate professionals as needed.

Marlowe A, Pepin MG, Byers PH. Testing for osteogenesis imperfecta in cases of suspected non-accidental injury. J Med Genet 2002;39:382-6.

Wardinsky TD, Vizacarrondo FE, Cruz BK. The mistaken diagnosis of child abuse: a three-year USAF Medical Center analysis and literature review. Mil Med 1995;160:15-20.


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