SMAD3 and aneurysm: Interestingly, molecular analysis performed on the proband did not detect any known mutations associated with aneurysms, i.e., in genes encoding components of the extracellular matrix (FBN1, COL3A1), in loci encoding ligand receptors, and downstream effectors of the TGF-β signaling pathway (TGFBR1, TGFBR2, SMAD3, SKI), and in genes encoding proteins and enzymes involved in the contractile unit of vascular smooth muscle cells (ACTA2, MYH11) [14].