What Is It?
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, and forms much of the structural support for other body tissues. It is a major component of tendons, ligaments, bones, cartilage and the walls of large blood vessels. In Marfan’s syndrome, a mutation (alteration) in a gene causes a defect in the body’s production of fibrillin, an important building block of connective tissue. A gene is a segment of DNA that directs production of a particular body protein. 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 defect in fibrillin production, people with Marfan’s syndrome have from many different problems related to weakness in connective tissue. These problems include:
- Reduced vision — About 65 percent of Marfan’s patients develop ectopia lentis. This is a dislocation of the lens of the eye, which is caused by a weakness in tiny eye ligaments that normally hold the lens in place. 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 arachnodactyly (long, slender, spiderlike fingers). They also may have severe chest deformities, such as pectus excavatum, in which the chest wall is caved in in front, or pectus carinatum, in which the chest wall protrudes in front. Some patients also have scoliosis (curvature of the spine).
- Cardiovascular changes — Structural weakness of connective tissue affects the heart and blood vessels of those with Marfan’s syndrome, so that cardiovascular problems are the major cause of Marfan’s-related illness and death. 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 aortic aneurysm (an abnormal swelling or dilatation), typically at the root of the aorta at the outlet of the heart. This dilatation 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).
The defect in the fibrillin gene does not cause predictable problems. Geneticists refer to this as penetrance. It seems that a given genetic defect can behave differently in different people. For example, in one person, the genetic defect causes no identifiable problems, and in another, the same defect appears to cause the complete Marfan’s syndrome. This is part of the reason Marfan’s syndrome affects members of the same family in potentially different ways.
Health experts estimate that about 200,000 people in the United States currently 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 severity of symptoms can vary. People with severe Marfan’s syndrome typically have:
- Long, thin extremities, with or without other skeletal changes
- Vision problems, including nearsightedness and ectopia lentis
- Aortic aneurysms, usually located at the root or base of the aorta, near the heart
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, especially if this death was attributed to heart problems.
Your doctor may suspect Marfan’s syndrome based on this family history, your personal history of ectopia lentis and your physical appearance (tall, thin, with arachnodactyly). The diagnosis can be confirmed if the patient has a history of ectopia lentis and also has an aortic aneurysm visible on echocardiography, 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 is also available in selected medical centers to 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 or reverse the inherited abnormality in fibrillin that affects people with Marfan’s syndrome. Marfan’s patients and their relatives may wish to seek genetic counseling to clarify their risk of passing the disorder to future generations.
There is no medical treatment to prevent or reverse the inherited abnormality in fibrillin that affects 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 beta-blockers. These medications, 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.
If you have Marfan’s, your doctor will monitor your cardiovascular health carefully with frequent echocardiograms to check for developing problems in the aorta and mitral valve. If a serious problem is found, you may need surgical replacement of the aortic valve, mitral valve or part of the aorta. In general, if the patient’s aortic root has stretched to more than 6 centimeters in diameter or if the thoracic aorta has widened to greater than 5 centimeters in diameter, the affected portion of the aorta is replaced surgically.
You should follow a non-strenuous exercise program that involves non-competitive, non-contact sports (walking, bicycling, jogging), in which you can participate at your own pace.
If you have Marfan’s-related scoliosis, you can be treated with bracing and physical therapy for scoliosis of 20 to 40 degrees, or with surgery for scoliosis greater than 45 degrees. To allow early diagnosis of Marfan’s-related eye problems, you should have an annual eye examination. If you have ectopia lentis, you may be able to be treated with aphakic lenses and special eye drops to widen the pupil, rather than surgery. If eye surgery is necessary, it should be performed in an ophthalmology center that specializes in the treatment of Marfan’s syndrome.
When To Call A Professional
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 percent to 95 percent 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.
Diseases and Conditions Center
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.