Marfan syndrome is a genetic (inherited) disorder in which connective tissue is not stiff enough to support certain structures throughout the body, including artery walls and heart valves. Marfan syndrome often affects the aorta, causing it to stretch (especially during exertion). This stretching (dilation) can lead to aortic dissection or aortic aneurysm.

Heart valves in people with Marfan syndrome may not be stiff enough to keep blood from flowing backward (regurgitation). Regurgitation can cause the heart to work harder in order to function properly. The aortic and mitral valves are most commonly affected. Over time, valve regurgitation can lead to enlargement of the heart. Symptoms of valve regurgitation may include fatigue, shortness of breath and chest pain (angina).

Marfan syndrome also increases the risk for mitral valve prolapse, a condition in which the mitral valve does not close properly and swings back into the left atrium. Mitral valve prolapse can also cause regurgitation.