Proteoglycan and collagen of "achondroplastic" (cn/cn) neonatal mouse cartilage

Proteoglycans and collagen were analyzed in epiphyseal cartilage of 5 day old mice homozygous for the recessive gene, achondroplasia, and their normal littermates. No significant differences were observed in either hydroxyproline or hexosamine content. Extractable proteoglycans from control and mutant tissue were found to contain a similar distribution of aggregate and monomer. The component glycosaminoglycans were similar in size and composition. Collagen from both was identified as type II collagen. In addition, the collagen content of hind limb bones of 28 day dwarf mice was found to be similar to control amounts. These findings suggest that dwarfism in the cn/cn mouse is not associated with a defect in any of the major matrix constituents.