Recently, genetic mutations in the components of elastin-contractile units have been reported as a cause of thoracic aortic aneurysm (TAA); the gene can be divided into two main categories, namely microfibril-related genes that make up elastic fibers [6,51,52,53] and genes that make up actomyosin contractile filaments in SMCs [35,36]. This evidence concerns the gene ELN and thoracic aortic aneurysm.