Marfan syndrome is a hereditary disorder affecting multiple systems in the body. Enlargement of the aorta is one of the most common and important features of this disease, and can lead to life-threatening problems, such as aortic dissection. Beta-blockers, have been recommended by guidelines as the first line medical treatment of Marfan syndrome, although the exact mechanism of action of beta-blockers in Marfan syndrome is not known.