FBN1 and Marfan syndrome: Grewal et al. (2016) underlined the common features of aortic wall involvement, with an alteration of fibrillin 1 expression and a lower differentiation of vSMC. However, in case of Marfan syndrome, histological abnormalities of the medial layer are diffuse and more severe (Della Corte et al., 2006; Waters et al., 2017). Marfan syndrome is clinically characterized by an earlier aortic dilation and a major risk of acute aortic event, much higher than in BAV (Detaint et al., 2014).