May have a role in bone formation and also in establishing the ordered structure of cartilage through matrix organization. Surrounding resting, proliferating, and hypertrophic chondrocytes. Confined to the middle zone of embryonic epiphyseal cartilage consisting of flattened chondrocytes and the ossifying region in the limb buds of chick embryos. Has also been detected in testis. Expression starts at 12.5 dpc and is restricted to developing cartilage. The O-linked polysaccharide on Ser-96 is probably the mucin type linked to GalNAc. There is one glycosaminoglycan chain, known to be dermatan sulfate, and it is probably the O-glycosylation at Ser-64 (By similarity). Belongs to the small leucine-rich proteoglycan (SLRP) family. SLRP class III subfamily.