Biglycan (BGN) is a member of the small leucine-rich repeat proteoglycan family (SLRPs) which also includes decorin, fibromodulin (Hedlund et al. 1994 - binding to collagen II), lumican and asporin (Hedbom & Heinegard 1993, Ezura et al. 2000). All appear to be involved in collagen fibril formation and matrix assembly (Ameye & Young 2002).

BGN-deficient mice exhibit larger and irregular fibrils leading to thin dermis and reduced bone mass (Corsi et al. 2002, Xu et al. 1998). BGN binds collagen types I (Schönherr et al. 1995), II (Bovine, using pig BGN - Vynios et al. 2001, Bovine, using bovine BGN - Douglas et al. 2008), III (Bovine, using bovine BGN - Douglas et al. 2008), VI (Wiberg et al. 2001) and IX (Chen et al. 2006 - species source of collagen/BGN unknown).