FBN1 and Marfan syndrome: Marfan syndrome (MFS) is an inherited autosomal connective tissue disorder caused by mutations in an extracellular matrix protein, fibrillin‐1 (FBN1), with manifestations in the cardiovascular system, eye, skeleton, lung, skin and dura.1 The major complication is aortic dissection, which generally occurs in the presence of aortic root dilatation.