FBN1 and Marfan syndrome: In cases without a family history of MFS, patients with aortic root dissection or dilatation (Z-score ≥2) and one of the three MFS-related manifestations (EL, FBN1 mutation, the system score ≥7) can be diagnosed with MFS, and MFS diagnosis is also confirmed by the presence of EL and FBN1 mutation associated with aortic disease.