Connective tissue disorders and smooth muscle disorders in cardiology

The hereditary disorders of connective tissue encompass a spectrum of clinically and genetically heterogeneous conditions caused by genetic defects in structural connective tissue proteins, such as collagen, fibrillin, and elastin. Clinical manifestations of these disorders are variable, and include musculoskeletal, skin, ocular, cardiovascular, and other visceral pathologies. Substantial overlap in clinical features between different disorders of connective tissue is present. Many connective tissue disorders constitute a risk of aneurysm formation and dissection of the aorta and/or other arteries, due to a defect of connective tissue within the vessel wall. Marfan syndrome is the most common syndromic presentation of ascending aortic aneurysm, but other syndromes including vascular Ehlers-Danlos syndrome and Loeys-Dietz syndrome also show ascending aortic aneurysms and the associated risk of aortic dissection and rupture. Familial segregation of the risk for ascending aortic aneurysm can also occur in the absence of associated systemic findings of connective tissue abnormalities in patients with familial Thoracic Aortic Aneurysms and aortic Dissections (TAAD), with or without structural heart defects such as bicuspid aortic valve, aortic coarctation, or patent ductus arteriosus.