RÉSUMÉ
Marfan syndrome is a systemic disorder of connective tissue, caused by mutations in the FBN1, TGFBR1 or TGFBR2 genes. This syndrome is characterized by involvement of three major systems, skeletal, ocular, and cardiovascular. The continuing improvements in molecular biology and increasing availability of molecular diagnosis in clinical practice allow recognition of Marfan syndrome in patients with incomplete phenotypes. Additionally, molecular analyses could also be used for preimplantation genetic diagnosis. The identification of a mutation allows for early diagnosis, prognosis, genetic counseling, preventive management of carriers and reassurance for unaffected relatives. The importance of knowing in advance the location of the putative family mutation is highlighted by its straightforward application to prenatal and postnatal screening.