A consistent finding in animal models of lung fibrosis is an increase in the synthesis of chondroitin-sulfate/dermatan-sulfate (CS/DS) GAGs associated with accumulation of versican, a large CS-containing PG that forms macromolecular aggregates with hyaluronic acid in the interstitial matrix, and of decorin, which plays a key role in regulating collagen fibril formation and the spatial arrangement of collagen fibers in the matrix [4]. The gene discussed is VCAN; the disease is pulmonary fibrosis.