A MORPHOLOGICAL AND ULTRASTRUCTURAL-STUDY OF BONE IN OSTEOGENESIS IMPERFECTA

A morphological and electron microscopic study of bone from patients w ith osteogenesis imperfecta (OI) has been performed. Bone from OI pati ents from various anatomical sites has been compared with that from no rmal, age-, site-, and sex-matched controls. The morphology of OI bone appeared variable among patients and sites of bone examined. Immature woven bone and a poor lamellar pattern were the significant morpholog ical features and demonstrated that OI could not be characterized on t he basis of a single histological pattern. At the ultrastructural leve l, a number of previously unreported features were evident. Abnormal c ollagen fibers and an altered mineral composition were found in many O I patients, however, the panoramic heterogeneity between clinical type s and indeed within a single clinical type made it difficult to classi fy OI in this manner. The presence of intermitochondrial inclusions co ntaining calcium and phosphorus and the presence of a stromal calcific ation in the bone in some OI patients suggested an abnormal mineral fo rmation. Qualitatively, no obvious difference in the number of osteobl asts or osteoclasts was observed. The morphology and ultrastructure of OI bone were good indicators of the disease and serve a role in asses sing the progress of a patient through diagnosis and treatment. This r eport presents new ultrastructural findings in collagen and in mineral formation in OI compared with normal human bone.