The MYH11 gene encodes the smooth muscle cell (SMC)-specific isoform of β-myosin heavy chain, a major specific contractile protein produced in SMC, and represents the most important candidate gene in the 16p13.11 region for the predisposition to thoracic aortic aneurysm and dissection (TAAD) [25]; heterozygous mutations in the MYH11 gene have been identified in individuals with familial TAAD and are thought to be able to disrupt SMC contractile function, leading to an early and severe decrease in the elasticity of the aortic wall [59]. This evidence concerns the gene MYH11 and Rare disease with thoracic aortic aneurysm and aortic dissection.