Neonatal Marfan syndrome : in utero presentation with aortic and pulmonary artery dilatation and successful repair of an acute flail mitral valve leaflet in infancy.

Neonatal Marfan syndrome (nMFS) is the rare and severe form of this connective tissue disorder with poor outcome due to progressive valvular insufficiency. We describe a case of nMFS suspected in utero, by fetal echocardiography, due to marked dilatation of both great arteries, which is the first description of fetal pulmonary artery dilatation in this disorder. The patient developed a flail mitral valve leaflet during the first year of life that was successfully repaired with an excellent medium-term result. This is the first report of this type of surgery in infancy.