FBN1 and Aortic dissection: Patients with PTC variants in the FBN1 gene had more severe aortic phenotypes than those with in-frame variants (Table 1, Fig. 1), including a higher risk of aortic dissection (11% vs. 7%) or surgery (25% vs. 17%), and a larger mean aortic root diameter, despite younger age (suggesting faster aortic root dilation).