FBN1 and Marfan syndrome: Supporting this assumption, correlations between increased circulating TGF-β levels and other pathologies with causative alterations in ECM components which lead to TGF-β dysregulation have been described, such as in Marfan syndrome, a genetic disease caused by mutations in FBN1, encoding fibrillin-1, an ECM protein that binds to latent TGF-β.