For 20 years, the clinical, genetic and therapeutic knowledge of Marfan syndrome made great progress. The new classification, allowing the diagnosis and published in 2010, is easier to use. The diagnosis remains sometimes difficult particularly during childhood, because of the great variability of expression of the disease, from neonatal Marfan syndrome, to a weak clinical expression and especially because of the evolution of the signs with the age, which no classification takes into account. The search for amutation in the FBN1 gene is long and expensive and must be reserved only for patients having a very strong diagnostic suspicion. The therapeutics is preventive and based on patient education, limitation of the sport, beta blockade therapy, regular echocardiography as well as aorta replacement. New treatments are at present on approval but did not make the proof of their efficiency. The global care of the patient, by taking into account difficulties about genetic origin of the disease, aesthetic and psychological consequences, allows an improvement of the quality of life.