BGN and osteoporosis: Osteoporosis-like phenotype andabnormalities of collagen fibrils observed in biglycan-deficient mice initiated a number ofinvestigations addressing the mechanisms of biglycan-dependent regulation of bone formationand collagen fiber assembly (Xu et al.1998; Ameye et al. 2002;Corsi et al. 2002; Bi et al. 2005; Bi et al. 2007; Zhang et al. 2009; Embree et al. 2010).