TGFB1 and pneumothorax: Fibrillin-1 aggregates also normally bind the large latent complex of the cytokine transforming growth factor β (TGF-β); in fibrillinopathies such as Marfan syndrome failure of this event results in increased TGF-β activation and systemic connective tissue manifestations such as aortic aneurysm, heart valve degeneration, and potential pneumothorax [16].