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Marfan syndrome is a genetic disorder that affects connective tissue. Connective tissue holds other tissues together. Because connective tissue is found throughout the body, Marfan syndrome can affect many body systems, including the heart, blood vessels, bones, eyes, lungs and skin. It does not affect intelligence. Signs and symptoms of Marfan syndrome can be mild or severe. They may be present at birth or become apparent in childhood or in adult life.

How common is Marfan syndrome?
Marfan syndrome affects more than 200,000 Americans (about 1 in 5,000 to 1 in 10,000) (1, 2). The disorder affects males and females of all races and ethnic groups. The condition is named for Dr. Antoine Marfan who, in 1896, described a 5-year-old girl with unusually long, slender fingers and limbs and other skeletal abnormalities.

How are individuals with Marfan syndrome affected?
Many affected individuals are tall, slender and loose-jointed. Arms, legs, fingers and toes often are unusually long. Some people with Marfan syndrome have low foot arches (flat feet), and others have high arches. Individuals with Marfan syndrome usually have long, narrow faces, and their teeth are generally crowded.

Individuals with Marfan syndrome can have one or more of the problems described below. The severity of the effects of Marfan syndrome varies greatly, even within the same family.

• Heart and blood vessel problems: The most serious problem associated with Marfan syndrome is weakness of the wall of the aorta. The aorta is the body’s largest artery, which carries oxygen-rich blood from the left side of the heart to the rest of the body.

In Marfan syndrome, the wall of the aorta gradually weakens and stretches (aortic dilation). Eventually, this can cause a tear (dissection) in the lining of the aorta. Blood can leak out through the tear into the aortic wall, sometimes causing a rupture that allows blood to leak into the chest or abdomen. If not detected and treated, these complications can cause sudden death.


• Abnormal heart valves: Heart valves are tiny flaps or gates that keep the blood flowing in one direction through the heart. With Marfan syndrome, the heart’s mitral valve tends to be large and floppy (mitral valve prolapse). An abnormal mitral valve can allow blood to briefly flow backwards during a heartbeat. Sometimes this creates an abnormal sound (heart murmur) that a health care provider may hear through a stethoscope. Mitral valve prolapse can sometimes be associated with irregular or rapid heartbeat and shortness of breath.


• Skeletal abnormalities: Many affected individuals have a lateral (sideways) curve of the spine called scoliosis. Sometimes there is a sharp, forward curvature called kyphosis. Many individuals have a breastbone that protrudes outward (called pectus carinatum) or sinks inward (called pectus excavatum). These chest abnormalities can sometimes affect heart or lung function.

Sometimes the connective tissue that surrounds the spinal cord loosens and stretches out. This condition is called dural ectasia and can cause pain in the lower back or legs and numbness or weakness in the legs.


• Lung problems: Persons with Marfan syndrome sometimes develop breathing problems, such as shortness of breath. Breathing problems may result from skeletal abnormalities that do not allow the chest to fully expand or from sudden collapse of the lungs (called spontaneous pneumothorax).

Adults with Marfan syndrome are at increased risk for early emphysema, a breathing disorder usually associated with smoking, even if they don’t smoke. Individuals with Marfan syndrome also may have short pauses in breathing during sleep, called sleep apnea.


• Eye problems: The lens of one or both eyes is off-center in more than 60 percent of persons with Marfan syndrome (1, 3). This is called ectopia lentis. Most affected individuals are nearsighted and have astigmatism (the eyes cannot focus clearly).
  
  Individuals with Marfan syndrome are at increased risk for detachment of the retina (tears in the light-sensing lining at the back of the eye), cataracts (clouding of the lens of the eye) and glaucoma (increased pressure in the eye). Individuals with Marfan syndrome often develop cataracts and glaucoma at an earlier age than individuals in the general population. Retinal detachment and glaucoma can lead to vision loss.

How is Marfan syndrome diagnosed?
An evaluation for Marfan syndrome generally includes:

• A complete physical examination.
• An eye examination by an ophthalmologist (eye doctor). The ophthalmologist uses eye drops to fully dilate the pupils of the eyes and examines them with a slit-lamp (a microscope with a light attached) to look for lens dislocation.
• Heart tests, including an electrocardiogram (EKG) and an echocardiogram. An EKG measures electrical activity in the heart. An echocardiogram is a noninvasive ultrasound that lets doctors look for involvement of the heart and blood vessels. Imaging tests, such as a computed tomography (CT scan) or magnetic resonance imaging (MRI), may be used to check the condition of the aorta.
• A family history to determine if there are other family members known or suspected to have Marfan syndrome and/or who died early due to an unexplained heart disorder or an aneurysm. An aneurysm is a bulging of a blood vessel, such as the aorta, that sometimes can cause the vessel to rupture.
• Genetic testing of a blood sample to help confirm the diagnosis.
• An MRI of the lower spine to look for dural ectasia.

How is Marfan syndrome treated?
Advances in treatment have greatly improved the outlook for children and adults with Marfan syndrome. Today, the life expectancy of individuals with the disorder who receive proper treatment is about 70 years (1, 2).

Most of the problems associated with Marfan syndrome can be managed effectively, as long as they are diagnosed early. The disorder usually is treated by a team of experienced physicians and health care professionals, overseen by a single doctor who knows all of its aspects.

The team of physicians should include a cardiologist (heart doctor). Affected individuals need to have a series of echocardiograms (called serial echocardiograms) to measure the dimensions of the aorta and check the condition of the heart valves. These and other tests help the doctors determine whether or not treatment is needed and when intervention should take place.

How are heart problems treated?
To help prevent or reduce heart problems, doctors often recommend treatment with high blood pressure medications called beta blockers. These medications reduce the strength and frequency of heartbeats, reducing stress on the wall of the aorta. Studies suggest that beta blockers may slow down the rate of dilation of the aorta and help prevent it from tearing (2, 4). Individuals who cannot tolerate beta blockers are sometimes treated with other high blood pressure medications, such as calcium channel blockers or angiotensin-converting enzyme inhibitors (4).

New studies suggest that high blood pressure medications called angiotensin-receptor blockers may help prevent or even reverse aortic dilation (5, 6). Larger studies are underway to test the effectiveness of these drugs.

In spite of the use of medication, the aorta sometimes continues to dilate. Doctors recommend surgery to repair the aorta before there is a danger of it tearing or dissecting. Doctors evaluate a number of factors when considering surgery and planning its timing. These factors include the size of the aorta and the rate at which it is dilating, family history of aortic dilation/dissection, and whether the aortic valve is leaking.

There are a few surgical options for repairing the aorta. In one operation, the surgeon replaces a section of the aorta with a synthetic tube (called a composite graft) and sometimes repairs or replaces the aortic valve. More recently, some individuals with Marfan syndrome have had a valve-sparing procedure in which the aortic valve is retained and a portion of the aorta closest to the heart is replaced.

Individuals with Marfan syndrome should have aortic surgery performed at a hospital where the surgeons are experienced with Marfan syndrome. Affected individuals should discuss the pros and cons of various surgical options with their surgeon.

Early preventive surgery for aortic dilation is safer than waiting until emergency surgery is needed. A 1999 study showed that with preventive surgery, the death rate was 1.5 percent vs. 12 percent for patients who had emergency surgery (7).

When necessary, other faulty heart valves can be surgically repaired or replaced. After any valve replacement surgery, the individual must take anti-clotting medication for life, because blood tends to clot when it comes in contact with artificial valves.

Individuals with Marfan syndrome who have had surgery to replace a heart valve or have certain heart abnormalities are prone to heart wall or heart valve infections (8). They must be treated with oral antibiotics to prevent infection before dental procedures (including cleaning, filling and extractions) that may release bacteria into the blood stream. All individuals with Marfan syndrome should check with their cardiologist to see if they need antibiotics before dental procedures (1).

Sometimes individuals with Marfan syndrome who have had repair of the upper portion of the aorta have enlargement of other parts of their aortas. These individuals need to be followed with serial echocardiograms and a CT scan or MRI of the chest, abdomen and pelvis at least yearly. In some cases, surgical repair may be needed.

How are skeletal problems treated?
Children and adolescents with Marfan syndrome are monitored yearly for signs of scoliosis. Many develop mild scoliosis, which may not require treatment.

In more severe or progressive cases, scoliosis can cause back pain and shortness of breath. In these cases, a brace or surgery is recommended. Bracing can sometimes halt the progression of scoliosis, although sometimes surgery is needed to correct the deformity.

Chest wall (pectus) abnormalities also can interfere with breathing. Corrective surgery can be performed to alleviate these symptoms.

How are eye problems treated?
Children and adults with Marfan syndrome should have a yearly eye examination by an ophthalmologist. Most eye problems, such as nearsightedness, can be corrected with glasses or contact lenses. Early treatment for cataracts and glaucoma usually can prevent or lessen vision problems. Detached retinas can be treated with lasers.

Can individuals with Marfan syndrome exercise?
Most individuals can benefit from mild forms of exercise. However, strenuous exercise can place stress on the aorta. Therefore, children and adults with Marfan syndrome should avoid strenuous exercise, including competitive, collision and contact sports (1, 3, 4). Heavy lifting also should be avoided. With their doctor’s guidance, many can participate in less vigorous activities, such as walking, slow jogging, playing golf, leisurely bicycle riding, swimming and slow-paced tennis (1).

What causes Marfan syndrome?
Marfan syndrome is caused by mutations (changes) in one member of a pair of genes called the fibrillin genes. These genes are located on chromosome 15, one of the 23 pairs of human chromosomes.

Normally, the fibrillin gene enables the body to produce fibrillin, a protein that is a crucial component of connective tissue. Fibrillin normally is an abundant component of the connective tissue found in the aorta, in the ligaments that hold the eye’s lenses in place, in bones and in the lungs.

Mutations in the fibrillin gene lead to the formation of insufficient or faulty fibrillin, which probably weakens connective tissue. Fibrillin also helps regulate the levels of a growth factor (called transforming growth factor-beta) that plays a role in tissue growth and repair. Recent studies suggest that excessive amounts of this growth factor are released in individuals with Marfan syndrome, contributing to the signs and symptoms of the disorder (2, 4).

How is Marfan syndrome inherited?
The mutated fibrillin gene usually is inherited from one parent who has Marfan syndrome. The mutation is a dominant genetic trait. This means that each child of a parent with Marfan syndrome has a 50 percent chance of inheriting the mutation and a 50 percent chance of not inheriting it. Only those children who inherit the mutation develop the signs and symptoms of Marfan syndrome.

About 25 percent of cases of Marfan syndrome are sporadic (1, 2). This means that they are caused by a new mutation that occurred by chance in one of the fibrillin genes in a sperm or egg cell of an unaffected parent. Parents who themselves do not have Marfan syndrome and do not have a family history of Marfan syndrome, but who have an affected child, should meet with a genetic counselor to discuss their risks in another pregnancy.

As with other inherited disorders, Marfan syndrome cannot be caught from another person. Although it may be diagnosed at any age, the signs and symptoms of Marfan syndrome do not occur unless the person has the mutation.

Is pregnancy risky for women with Marfan syndrome?
There are several important issues for women with Marfan syndrome who are considering pregnancy. There is a 50 percent chance of having a child with Marfan syndrome with each pregnancy. In addition, the stress of pregnancy may cause rapid enlargement of the aorta, especially if the aorta is significantly enlarged before pregnancy (1, 3, 4). The risk of the aorta tearing is low, but not zero, in women with Marfan syndrome who have a normal aortic size. The risk increases during pregnancy as the aorta enlarges.

Women with Marfan syndrome should consult their health care providers and their cardiologist before pregnancy to discuss whether pregnancy is safe for them. The cardiologist generally recommends an echocardiogram to determine the dimensions of the aorta.

During pregnancy, an affected woman should receive prenatal care from a high-risk obstetrician who has experience with Marfan syndrome. She should also see her cardiologist regularly. She needs to have an echocardiogram in the first, second and third trimesters to monitor the size of her aorta (1, 3). If the aorta measures less than 4 cm, there is a low risk of tears during pregnancy (1, 4).

Women who are taking a beta-blocker generally can safely continue taking the medication throughout pregnancy. Those who have had a valve replaced usually are on an oral blood thinner called coumadin (warfarin). Because this drug increases the risk of birth defects, pregnant women are switched to another blood thinner called heparin, which is given by injection (usually two or three times a day), during pregnancy.

Women with Marfan syndrome do not appear to have an increased risk of miscarriage (1). Most women with Marfan syndrome can have a vaginal delivery. The doctor will take appropriate measures to lessen the stress of labor and birth. However, if the woman has significant aortic dilation, a cesarean birth may be recommended (1).

A woman with Marfan syndrome should have a follow-up echocardiogram at 1 to 2 months after delivery to check the size of her aorta (1).

Can Marfan syndrome be prevented?
At present, there is no way to prevent Marfan syndrome. Early diagnosis can help prevent serious complications. Genetic counseling enables informed decisions about childbearing and provides up-to-date information about the genetic basis of Marfan syndrome and genetic testing for this condition.

What research is being done on Marfan syndrome?
In 1991, researchers funded, in part, by the March of Dimes, discovered the gene that causes Marfan syndrome and identified the protein controlled by this gene (9). Since then scientists have discovered more than 1,000 mutations within the fibrillin gene (4). Researchers are learning more about the role the fibrillin gene plays in the growth and development of connective tissue. A clinical trial that started in 2007 is comparing the effectiveness of two different medicines in preventing or decreasing the rate of progression of aortic dilation (5).

For more information

• National Marfan Foundation 

References

1. National Marfan Foundation. Living With Marfan Syndrome. Accessed 12/5/08.
2. Pearson, G.D., et al. Report of the National Heart, Lung, and Blood Institute and National Marfan Foundation Working Group on Research in Marfan Syndrome and Related Disorders. Circulation, volume 118, number 7, August 12, 2008, pages 785-791.
3. National Heart, Lung and Blood Institute. Marfan Syndrome. Accessed 12/1/08.
4. Keane, M.G. and Pyeritz, R.E. Medical Management of Marfan Syndrome. Circulation, volume 117, number 21, May 21, 2008, pages 2802-2803.
5. Brooke, B.S., et al. Angiotensin II Blockade and Aortic-Root Dilation in Marfan’s Syndrome. New England Journal of Medicine, volume 358, number 26, June 26, 2008, pages 2787-2795.
6. Ahimastos, A.A., et al. Effect of Perindopril on Large Artery Stiffness and Aortic Root Diameter in Patients With Marfan Syndrome. Journal of the American Medical Association, volume 298, number 13, October 3, 2007, pages 1539-1547.
7. Gott, V.L., et al. Replacement of the Aortic Root in Patients with Marfan’s Syndrome. New England Journal of Medicine, volume 340, number 17, April 29, 1999, pages 1307-1313.
8. American Heart Association. Marfan Syndrome. Accessed 11/26/08.
9. Lee, B., et al. Linkage of Marfan Syndrome and a Phenotypically Related Disorder to Two Different Fibrillin Genes. Nature, volume 352, July 25, 1991, pages 330-334.

January 2009