Marfan Syndrome: MFS is a rare multisystemic HCTD with autosomal dominant transmission and the following characterising features: thoracic aortic aneurysm (TAA) at the sinus of Valsalva, and/or thoracic aortic dissection (TAD), ectopia lentis, systemic features (SF) with a score indicating the presence of such manifestations =/> 7 to be positive for the clinical diagnosis, in addition to a positive family history (FH) among first relatives and the detection of a pathogenic fibrillin 1 gene (FBN1) mutation already described in patients with thoracic aorta aneurysm/dissection (TAAD) [2]. The gene discussed is FBN1; the disease is thoracic aortic aneurysm.