TGFB1 and Marfan syndrome: In addition, infiltrating CD45+ cells in the aortic root adventitia as the disease progresses, might also contribute to excessive TGF-β1 production.405 SGS is caused by mutations in the Sloan-Kettering Institute (SKI) proto-oncoprotein, 408,409 and results in similar physical features as MFS plus craniosynostosis.