Structural and Signaling Mechanisms of Aortic Wall Failure in Heritable Thoracic Aortic Disease.

Heritable thoracic aortic diseases (HTAD) are inherited conditions that increase the risk of thoracic aortic aneurysms, dissections, and premature aortic rupture. Advances in human genetics and experimental models have transformed our understanding of these disorders from a phenotype-based classification system to a mechanism-based view involving extracellular matrix (ECM) architecture, transforming growth factor-β (TGFβ) signaling, and vascular smooth muscle cell contractility. Marfan syndrome, Loeys-Dietz syndrome, and nonsyndromic HTAD demonstrate how genetic mutations can disrupt the components that stabilize the aortic wall. These pathogenic mechanisms influence matrix organization, intracellular signaling, and the contractile machinery within the mechanically stressed proximal aorta. In this review, we summarize current mechanistic insights into the major forms of HTAD and discuss how new molecular and cellular concepts could influence surveillance, genetic counseling, and genotype-guided therapeutic strategies.