The SMAD3 gene represents 5–10 percents of the transforming growth factor β (TGFβ) vasculopathies (TGFβvs), caused by a defect in the TGFβ pathway genes such as TGFBR1, TGFBR2, TGFB2, TGFB3 and SMAD2. There is a clinical overlap between these TGFβvs and Marfan syndrome (MFS) in which the aortic aneurysm/dissection events dominate the cardiovascular phenotype. The gene discussed is TGFBR1; the disease is Marfan syndrome.