More recently, we and others identified pathogenic mutations in the genes encoding the TGF-β receptor (TGFBR) subunits TGFBR1 and TGFBR2 5, 6, the signaling transducer SMAD3 (7), the ligand TGFB2 8, 9, and the inhibitor SKI (10), occurring predominantly in patients with syndromic presentations of thoracic aortic aneurysms and dissections (TAAD), designated Loeys-Dietz syndrome (LDS1 [MIM 609192] [11]; LDS2 [MIM 610168] [11]; LDS3 [MIM 613795] [also known as aneurysms-osteoarthritis syndrome] 7, 12, 13, LDS4 [MIM 614816] [8]), and Shprintzen-Goldberg syndrome (SGS [MIM 82212]) 13, 14. Here, SMAD3 is linked to Loeys-Dietz syndrome.