Glycosaminoglycans of cartilage and bone tissue in two cases of osteogenesis imperfecta congenita.

Epiphyseal cartilage and bone tissue from two cases of osteogenesis imperfecta congenita and one control case with similar skeletal age were examined regarding their glycosaminoglycan content. The diseased bone tissue showed a 3-fold increase in glycosaminoglycans, and 20-25 per cent of the chondroitin sulphate disaccharides seemed to be disulphated. The diseased cartilages showed only traces of material with characteristics of disulphates disaccharides. No disulphates disaccharides were isolated from the control materials. No difference between diseased and control material was indicated regarding molecular size, chondroitin-4-sulphate/chondroitin-6-sulphate ratio or contents of keratan sulphate and hyaluronic acid. The disease is thus associated with fundamental changes of the glycosaminoglycan structure, and these changes may be of functional importance to the mineralization process as well as to the organisation of collagen.