Marfan's syndrome is a genetic (inherited) disorder that affects the body's connective tissue. Connective tissue is the tough, fibrous, elastic tissue that connects one part of the body with another. It is a major part of tendons, ligaments, bones, cartilage and the walls of large blood vessels. In Marfan's syndrome, the body can't produce enough fibrillin, an important building block of connective tissue.
The problem in Marfan's syndrome is caused by a mutation (change) in a gene. Genes are segments of DNA that direct the body to produce proteins. In many families with inherited Marfan's syndrome, the mutation affects the FBN1 gene on chromosome 15, although a second gene on chromosome 5 may be involved in some cases.
Because of the inherited problem producing fibrillin, people with Marfan's syndrome have from many different problems related to weakness in connective tissue. These problems include:
- Reduced vision. In about 65% of Marfan's patients, the lens of the eye becomes dislocated because tiny eye ligaments that normally hold the lens in place are weak. This condition is called ectopia lentis. Marfan's syndrome also seems to increase the risk of myopia (nearsightedness), cataracts at an unusually early age (age 40 to 50), glaucoma, retinal detachment and strabismus .
- Skeletal abnormalities. Patients with Marfan's syndrome are typically very tall, with long limbs and long, slender, spiderlike fingers. They also may have severe chest deformities, such as a chest that is either caved in or protrudes in front. Some patients also have scoliosis (curvature of the spine).
- Cardiovascular changes. Weakened connective tissues affect the heart and blood vessels of people with Marfan's syndrome. Cardiovascular problems are the major cause of illness and death related to Marfan's syndrome. In people with Marfan's syndrome, connective tissue weakness can cause mitral valve prolapse (a "floppy" mitral valve that doesn't close properly) or mitral valve regurgitation (a severe problem in closing the mitral valve that results in a significant backflow of blood into the left atrium). It also can lead to an abnormal swelling or dilatation (aneurysm) in the heart's main artery, the aorta, typically at the root of the aorta where it leaves the heart. This aneurysm can lead to aortic regurgitation (abnormal backflow of blood when the heart tries to pump blood forward), aortic dissection (a spreading tear in the inner wall of the aorta that causes a separation between the aorta's inner and outer layers) and aortic rupture (a break in the wall of the aorta, with leakage of blood).
Health experts estimate that about 200,000 people in the United States have Marfan's or related syndromes, and the disorder probably affects one out of every 10,000 newborns.
Marfan's syndrome affects each person differently, and the presence and severity of symptoms can vary. Most often, people with Marfan's become aware of the disorder after they find out that someone else in their family has it or because of their appearance. People with Marfan's syndrome typically are tall with long, thin extremities, with or without other skeletal changes.
Vision problems, including nearsightedness and ectopia lentis, usually develop. The symptoms such as chest pain and shortness of breath can be very dramatic if there is expansion of an aortic aneurysm or heart valve damage.
Your doctor will ask about any family history of Marfan's syndrome, as well as about any family members who are unusually tall and thin, whether or not they have vision problems. Your doctor also may ask about any family history of sudden death resulting from aortic dissection or rupture.
Your doctor may suspect Marfan's syndrome based on this family history and your physical appearance. The diagnosis can be confirmed if you have a history of ectopia lentis and also have a dilated aortic root (the first part of the aorta as it exits the heart) visible on echocardiography. Echocardiography is a painless test that uses sound waves to outline the structure of the heart and its major vessels. The diagnosis will be even more certain if you have other skeletal abnormalities (chest wall deformities or scoliosis), or heart murmurs due to aortic or mitral valve abnormalities. Genetic testing can check for specific chromosomal abnormalities related to abnormal fibrillin production.
Marfan's syndrome is a lifelong illness that is present at birth.
There is no way to prevent Marfan's syndrome. Marfan's patients and their relatives may wish to seek genetic counseling to talk about their risk of passing the disorder to their children.
There is no medical treatment to reverse the fibrillin abnormality in people with Marfan's syndrome. In the future, research on a strain of mice that are born with similar fibrillin problems may lead to a successful treatment for Marfan's.
Until then, doctors try to prevent or delay the aortic changes seen in Marfan's patients by prescribing medication that decreases the pressure inside the aorta. Your doctor may advise that you take a beta-blocker and/or an angiotensin receptor blocker called losartan (Cozaar). Beta blockers, such as propranolol (Inderal), metoprolol (Lopressor) and atenolol (Tenormin), decrease the strain on the aorta's wall by slowing the heart rate and reducing the force of heart contractions, especially during exercise. Losartan and other angiotensin receptor blockers help lower blood pressure, which reduces the stress on artery walls.
If you have Marfan's, your doctor will monitor your heart health with periodic echocardiograms to check for developing problems in the aorta and mitral valve. If a serious problem is found, you may need surgery to replace the aortic valve, mitral valve or part of the aorta. Doctors become concerned when the aortic root size measured on an echocardiogram expands over time. Once it reaches 5 centimeters or more, many experts recommend surgery. Some recommend surgery with lesser aortic root enlargement.
You should follow a non-strenuous exercise program that involves non-competitive, non-contact sports (walking, bicycling, jogging), which you can do at your own pace.
If you have Marfan's-related scoliosis of 20 to 40 degrees, you can be treated with a brace and physical therapy. For scoliosis greater than 45 degrees, you will need surgery. You should have an annual eye examination to look for Marfan's-related eye problems. If you have ectopia lentis, you may be able to be treated with special lenses called aphakic lenses and special eye drops to widen the pupil, rather than surgery. If eye surgery is necessary, it should be done in an ophthalmology center that specializes in the treatment of Marfan's syndrome.
Call your doctor whenever you have vision problems. In many Marfan's patients, the eye doctor (ophthalmologist) is the first to suspect Marfan's syndrome based on findings during a vision exam. Also call your doctor if you have chest pain, shortness of breath, especially during exercise, or an irregular pulse.
If you know that you have Marfan's syndrome, call your doctor immediately if you experience severe pain in the front or back of the chest, sudden weakness or tingling in the legs or arms, or an unexplained fever. These may be symptoms of aortic dissection, a medical emergency that can lead to aortic rupture, which is fatal in 90% to 95% of cases.
Despite the high risk for Marfan's-related cardiovascular problems, the average life expectancy of those with Marfan's syndrome is nearly 70 years.
The National Marfan Foundation
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