Among 306 patients we have examined, genetic testing was performed in 35: in 11, the diagnosis of Marfan syndrome was confirmed; in 7, the diagnosis of Loeys–Dietz syndrome was confirmed; in 5, the diagnosis of Ehlers–Danlos was confirmed; and in 12 patients, no pathogenic or potentially pathogenic mutation was found (these patients were diagnosed for mutations in the FBN1 gene). This evidence concerns the gene FBN1 and Marfan syndrome.