[Marfan's syndrome. Cardiovascular manifestations and therapeutic indications].

Marfan's syndrome is a disease of collagen microfibrils, the essential composition of which, fibrillin, is defective. The coding gene of this large protein has been localised on chromosome 15 and partially cloned. Its mutation is transmitted in the autosomal dominant mode. It is common, affects many organs, especially those rich in collagen. They include the skeleton, the eye and cardiovascular system. The prognosis of these patients depends on the degree of cardiovascular involvement; the aorta is the principal site of the lesions, particularly the aortic root which tends to develop aneurysmal dilatation, then dissection, the main cause of premature death of these patients. Mitral valve prolapse giving rise to mitral regurgitation may also be observed. Much progress has been made is recent years in the management of Marfan's syndrome, especially in ultrasound follow-up of the aortic root and the definition of risk factors for dissection. In parallel, advances have been made in the treatment, both medical with the use of betablockers to try to slow progression to aneurysm, and surgical, in replacement of the aorta and aortic valve in time and under optimal conditions. Life expectancy is thereby significantly increased. Similar progress has been made to allow these patients to have a pregnancy, classically thought to carry a high risk of maternal death.