Bone histomorphometry in adults with type IA osteogenesis imperfecta.

A histologic and histomorphometric analysis was performed on undecalcified bone from 8 adult patients, ages 34 to 64 years, with Type IA osteogenesis imperfecta. Complete histomorphometric data, including static and dynamic parameters of bone remodeling, could be generated on 6 patients, and partial data were obtained from the other 2 patients. Findings in some patients of reduced eroded surfaces and reduced osteoid surfaces suggested low bone turnover. Other findings included normal or slightly reduced labeled surfaces, slightly reduced bone formation rate, decreased cortical thickness, and decreased bone volume. Histologic examination results showed lamellar bone with mature cortical Haversian systems. Trabeculae showed qualitatively normal connectedness despite low trabecular volume. The finding of normal or reduced bone turnover in adults with Type IA osteogenesis imperfecta has not been reported. Earlier histomorphometric studies, performed without correlation with a specific age or phenotype, indicated high bone turnover. The present study suggests that future research should correlate histopathologic changes with specific phenotypes. The finding of normal or slightly reduced bone turnover in Type IA osteogenesis imperfecta may have important therapeutic implications for this phenotype.