Among multiple functional domains, FBN1 contains nine TGFβ binding domains that are highly homologous to latent TGFβ binding proteins (Isogai et al. 2003; Hubmacher et al. 2006). Once secreted, FBN1 monomers aggregate and form beaded structures, which form macro-aggregates, microfibrils (Ramirez and Dietz 2007). Within these microfibrils, FBN1 sequesters TGFβ and BMPs in the ECM (Isogai et al. 2003; Sengle et al. 2008; Ramirez and Rifkin 2009). In patients with Marfan syndrome, defects in FBN1 lead to excess TGFβ signaling, which results in the pleiotropic manifestations of disease (Ramirez and Dietz 2007).