Diseases & Conditions


Marfan Syndrome

Marfan syndrome is a rare disorder of connective tissue, resulting in abnormalities of the eyes, bones, heart, blood vessels, and central nervous system.

This syndrome is caused by mutations in the gene that codes for a protein called fibrillin. Typical symptoms can range from mild to severe and include long arms and fingers, flexible joints, and heart and lung problems. The diagnosis is based on symptoms and family history. Most people with this syndrome live into their 60s. There is no cure for Marfan syndrome or any way to correct the abnormalities in the connective tissue.

Marfan syndrome is caused by dominant mutations in the gene that encodes a protein called fibrillin. Fibrillin helps connective tissue maintain its strength, and, therefore, some fibers and other parts of connective tissue undergo changes that ultimately weaken the tissue. The weakening affects bones and joints as well as internal structures, such as the heart, blood vessels, and eyes. Weakened tissues stretch, distort, and can even tear. For example, the aorta may weaken, bulge, or tear. Connective tissues that join structures may weaken or break, separating formerly attached structures. For example, the eye's lens or retina may separate from its normal attachments.

Symptoms can range from mild to severe. Many people with Marfan syndrome never notice symptoms. In some people, symptoms may not become apparent until adulthood. People with Marfan syndrome are taller than expected for their age and family. Their arm span (the distance between fingertips when the arms are outstretched) is greater than their height. Their fingers are long and thin. Often, the breastbone (sternum) is deformed and pushed either outward or inward. The joints may be very flexible. Flat feet and a humpback with an abnormal curve of the spine (kyphoscoliosis) are common, as are hernias. Usually, the person has little fat under the skin. The roof of the mouth is often high.

Marfan's Syndrome

The most dangerous complications develop in the heart and lungs. Weakness may develop in the connective tissue of the wall of the body's main artery, the aorta. The weakened wall may either result in blood seeping between the layers of the aorta's wall (aortic dissection), or in a bulge (aneurysm) that can rupture (see Aneurysms and Aortic Dissection: Aortic Dissection ).

Pregnancy increases the risk of dissection. Delivery by caesarean section is often recommended to minimize the risk.

If the aorta gradually widens, the aortic valve, which leads from the heart into the aorta, may begin to leak (aortic regurgitation). The mitral valve, which is located between the left atrium and ventricle, may leak or become prolapsed (bulge backward into the left atrium (see Heart Valve Disorders: Mitral Valve Prolapse (MVP) ).

These heart valve abnormalities can impair the heart's ability to pump blood. Abnormal heart valves can also develop serious infections (infective endocarditis). Air-filled sacs (cysts) may develop in the lungs. The cysts may rupture, bringing air into the space that surrounds the lungs (pneumothorax—(see Pleural Disorders: Pneumothorax ).

The lens of one or both eyes may be displaced (dislocated) in Marfan syndrome. The light-sensitive area at the back of the eye (retina) may detach from the rest of the eye. Displacement of the lens and detachment of the retina may cause permanent loss of vision.

Doctors may suspect the diagnosis if an unusually tall, thin person has any of the characteristic symptoms, or if Marfan syndrome has been recognized in other family members.

It is most important for doctors to monitor for complications that can cause serious symptoms. Echocardiography is used to evaluate the heart and aorta and is usually repeated yearly. A magnetic resonance imaging (MRI) scan can also evaluate heart and brain problems. X-ray studies of the hand, spine, pelvis, chest, foot, and skull are done to check for abnormalities. The eyes are usually examined yearly. Echocardiography and eye examinations are also performed whenever symptoms develop.

Prognosis and Treatment

Years ago, most people with Marfan syndrome died in their 30s. As of the late 1990s, most people with Marfan syndrome live until their 60s. Prevention of aortic dissection and rupture probably explains why the life span has been lengthened.

There is no cure for Marfan syndrome or any way to correct the abnormalities in the connective tissue. Treatment is aimed at preventing and fixing abnormalities before dangerous complications develop. Beta-blockers (such as atenolol Some Trade Names TENORMIN and propranolol Some Trade Names INDERAL ) are given to make blood flow more gently through the aorta. If the aorta has widened or developed an aneurysm, the affected section can be repaired or replaced surgically. Pregnant women are at especially high risk of complications with their aorta, so repair of the aorta before conception should be discussed. A displaced lens or retina can usually be reattached surgically.

Last full review/revision February 2008 by Frank Pessler, MD, PhD; David D. Sherry, MD

Source: The Merck Manual Home Edition