Elevated accumulation of hyaluronate in the tubular bones of osteogenesis imperfecta

The content and composition of glycosaminoglycans in the tubular bones of osteogenesis imperfecta were compared to those in the tubular bones of age-matched controls. Chondroitin sulfate was the major glycosaminoglycan (70-80% of total) both in the normal and pathological bones, and its level, based on the tissue wet weight, was slightly less in the pathological bones. The composition of chondroitin sulfate disaccharide units in the pathological samples was different from those of the control; a lower proportion of chondroitin 4-sulfate unit. Hyaluronate accounted for at most 7% of total glycosaminoglycans from the normal bones. The hyaluronate content of the pathological bones was 1.5- to 3-fold higher than that of the controls. Glycosaminoglycans have been shown to participate in the formation of a functional supramolecular complex in extracellular matrices. Therefore, it may be postulated that the abnormalities in glycosaminoglycan composition in the tubular bones of osteogenesis imperfecta is implicated in some clinical aspects of this connective tissue disorder such as the bony fragility.