CT bone density of the radius was measured in individuals with OI-type 1 in two unrelated families. The affected adults in these families noted a decreasing fracture frequency as they got older. CT bone density measurement is the most accurate and precise of any method for bone density and can determine both the trabecular bone density [TBD] and the cortical bone density[CBD]. The results are shown below: Table The results indicate that both children and adults with OI-type 1 have abnormal bone density, and there is an evolution with age from a bone of low TBD and low CBD in childhood to a bone of low TBD and high CBD in adulthood. This change reflects an increase in bone strength with age, and may explain the observation that individuals with OI-type I have less fractures as they get older.

Table 1
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