Modern HTAD gene panels now include more than 30 genes known to confer risk for thoracic aortic aneurysm and dissection, encompassing extracellular matrix genes (e.g., FBN1, COL3A1), smooth muscle contractile protein genes (e.g., ACTA2, MYH11, MYLK), and TGF-β signaling genes (e.g., TGFBR1, TGFBR2, SMAD3) [7]. The gene discussed is SMAD3; the disease is thoracic aortic aneurysm.