In contrast to these direct connective tissue disorders (COL3A1 and FBN1 mutations), well over a decade later it was discovered (in 2005) that mutations to genes (TGFBR1, TGFBR2) that encode receptors of the transforming growth factor-β (TGF-β) system also predispose to thoracic aortopathies [197,219]. Here, COL3A1 is linked to connective tissue disorder.