Newly synthesized proteoglycans in pseudoachondroplasia.

In an attempt to elucidate the biochemical defect in pseudoachondroplasia, proteoglycan metabolism was investigated in cartilage from a patient with the dominant form of this condition. Iliac-crest cartilage was radioactively labeled with 35S-sulfate and the newly synthesized proteoglycans examined for their hydrodynamic size and glycosaminoglycan composition. The banding pattern of the purified proteoglycans was analyzed by gel-electrophoresis using large pore polyacrylamide-agarose. We found a normal chain-length of glycosaminoglycans and a normal ratio of chondroitin-6-sulfate to chondroitin-4-sulfate. The proteoglycans were not enriched in keratan sulfate. Gel electrophoretic analysis of the proteoglycans disclosed a banding pattern comparable to that of two normal controls. In contrast to the findings of other authors no differences between the proteoglycans of pseudoachondroplastic and normal cartilage were detected.