FBN1 and Marfan syndrome: In patients with MFS, FBN1 mutation leads to fibrillin-1 deficiency causing activation of transforming growth factor-β (TGF-β) signaling pathways with improvement of collagen synthesis and elastic fiber disruption in cardiac and vessel wall connective tissue.[15] This remodeling increases aortic stiffness and decreases vasoreactivity resulting in aortic dilatation, impaired diastolic ventricular relaxation, and hypertrophic remodeling.[15]