Marfan Syndrome

Causes

Marfan syndrome is pretty rare, affecting about 1 in every 5,000 people. Researchers have traced the disorder to a defect in a gene found on chromosome 15. It's this mutation (change) that causes the abnormality in the production or the structure of fibrillin.

About 75% of the time, the gene for Marfan syndrome runs in families, getting passed down to kids from parents who have the disease. The gene is autosomal dominant, which means every child born to a parent who has Marfan syndrome has a 50% chance of having it too.

In the remaining 25% of cases, though, neither parent has the disease; the genetic mutation responsible for Marfan syndrome occurs spontaneously in either the egg or sperm cell at the time of conception. No one knows what causes this mutation, but those born with it have a 50% chance of passing it on to their kids.

Although people with Marfan syndrome often have similar physical features, the disease doesn't affect everyone in the same way. Some have very mild symptoms, while others have severe ones — even within the same family. This is known as "variable expression," and it makes it almost impossible to predict how the disease will progress in any affected individual.

Signs and Symptoms

People with Marfan syndrome are often (but not always) much taller than their family members and peers and have a lean, lanky build. Their fingers and toes are usually long and thin, and their joints are loose. Their arms and legs are often disproportionately long when compared with their torso, and their arm span is often a lot greater than their height.

They may share some facial characteristics, too, including a long, thin face; deep-set eyes; a small jaw; a high, arched roof of the mouth; and crowded teeth.

Complications

People with Marfan syndrome are also susceptible to complications in the following body systems:

Heart and Blood Vessels

The most serious complication of Marfan syndrome involves the heart. Over time, the disorder can cause the aorta — the large artery that carries blood away from the heart to the body — to stretch and dilate (widen).

If undetected or untreated, the wall of the aorta can eventually begin to tear and separate, allowing blood to leak through (this is known as an aortic dissection). A large, sudden rupture can be fatal.

Problems with the heart valves are common too. Instead of closing tightly, valves (usually the mitral and/or aortic valves) may become large and floppy, allowing blood to leak backwards through the heart. A minor leak may cause few symptoms, but a large one can cause shortness of breath and an irregular heartbeat, as well as a heart murmur. Leaky heart valves cause the heart to work harder and become enlarged, so they must be carefully monitored.

Eyes

More than half of all people with Marfan syndrome have a condition known as "dislocated lenses." That means the lenses of the eye, which are usually centered behind the pupil and held in place with connective tissue, may shift up, down, or to the side. Vision problems may occur depending on the position of the lens. The vision problems may require glasses at first, and later may require surgery.

People with Marfan syndrome also often have myopia (nearsightedness), and they are at greater risk for developing other problems — like detached retinas (when the light-sensing tissue at the back of the eye comes loose), glaucoma (high pressure in the eye), or cataracts (cloudy lenses) — earlier in life than other people. Young children are especially prone to developing amblyopia (lazy eye).

Skeletal Problems

In addition to excessive height and long limbs, Marfan syndrome may cause other skeletal problems, such as scoliosis (curvature of the spine) and chest wall abnormalities (the chest bone may either curve in or protrude out, giving the chest a sunken-in or a pigeon-breasted appearance). Overly loose joints and flat feet are common.

Other symptoms may affect the skin, nervous system, and lungs, but these tend to be less common and less serious, especially in kids and teens.

Diagnosing Marfan Syndrome

There's no single test for diagnosing Marfan syndrome. Diagnosis depends on detailed exams by a team of doctors, including a geneticist (a doctor who specializes in inherited disorders), a cardiologist (heart specialist), ophthalmologist (eye doctor), and an orthopedist (bone specialist). Molecular testing for a mutation in the FBN1 gene is part of the comprehensive evaluation.

First, a geneticist will ask about any family history of the disorder or whether any relatives died early from heart-related deaths. He or she may also take detailed skeletal measurements. The geneticist may order mutation testing on a small blood sample.

A cardiologist may listen for a heart murmur and will likely perform tests such as:

• a chest X-ray
• an electrocardiogram (EKG), which measures electrical activity in the heart
• an echocardiogram, which uses sound waves to produce a picture of the heart to check the size of the aorta and the functioning of the valves

An ophthalmologist may perform a "slit lamp" test (a slit lamp allows the doctor to see the front of the eye under high magnification) while the eyes are dilated to check for lens dislocation and any other abnormalities.

An orthopedist will check for curvatures of the spine and chest bone, as well as joint problems and flat feet.

Diagnostic Criteria

The criteria for diagnosis of Marfan syndrome are complex, mainly because many features of the syndrome also appear in the general population (obviously, not every tall, thin person with long fingers has the disorder), and because other connective tissue diseases have overlapping features. Recently, the criteria have been adjusted to consider the presence of a mutation in the FBN1 gene in the evaluation.

If there's already a family history established, a diagnosis of Marfan syndrome can be based upon problems in two of the body systems known to be affected.

If there's no family history, diagnosis requires very specific findings in several different systems. This can be frustrating for parents because symptoms may not appear during childhood but emerge over time, and a definitive diagnosis can sometimes take years. Finding a mutation in the FBN1 gene can help confirm a diagnosis.

Fortunately, doctors can treat symptoms even before there's a firm diagnosis.

Monitoring and Treatment

Kids and teens with Marfan syndrome must be followed closely by a team of doctors. Because their bodies grow and change so quickly, most will need echocardiograms at least once a year, plus frequent eye and bone exams. This helps doctors stay on top of any new problem.

Kids and teens with Marfan syndrome can do many things to help keep themselves healthy. The most important is to avoid putting extra stress on the heart. That means avoiding contact sports or any activity that involves a lot of running, muscle straining, or the risk of a blow to the chest — things like basketball, football, baseball, gymnastics, weightlifting, and track, to name a few.

Keeping Active

Kids with Marfan syndrome are not destined to be couch potatoes. They can and should play, exercise, and generally be active — they just have to learn to be a little more careful. Although a doctor should always have the final say about what activities are safe, things like non-competitive bike riding, swimming, dancing, walking — anything that's low-impact and can be done at a slower pace — usually get the green light.

Many of the complications of Marfan syndrome can be managed with medications and, if necessary, surgery. Medications known as beta blockers work to lower blood pressure and reduce wear and tear on the blood vessels, and can often delay the progression of aortic dilation. If the aorta does eventually widen to a potentially dangerous size, or if valve leakage becomes a problem, surgery may be recommended either to repair or replace the damaged parts of the heart.

Kids who are nearsighted or who have amblyopia (lazy eye) will probably have to wear glasses. Teens may be able to wear contact lenses. In some cases, if the lens of the eye becomes severely dislocated or if there are other complications, surgery may be necessary.

Kids who develop scoliosis may have to wear a special back brace. Sometimes severe cases of scoliosis and chest wall abnormalities may require surgery. Some teens may want to have surgery for cosmetic reasons.

Anyone with heart problems associated with Marfan syndrome (especially anyone who's had heart surgery) should always take antibiotics before going to the dentist to prevent bacterial endocarditis, an infection of the walls of the heart caused when bacteria enter the bloodstream.

It is recommended that kids and teens with Marfan syndrome wear a medical alert bracelet, in case there is an accident and the patient can't explain his or her medical condition.

Teen girls with Marfan syndrome should also be made aware that pregnancy puts extra strain on the heart and may increase the risk of damage to the aorta.

Caring for Your Child

It's not easy to learn your child has a genetic disorder. It's normal to have a whole range of emotions, from fear and anger to sadness and guilt. But the genetic mutation that causes Marfan syndrome is nobody's fault and could not have been prevented.

The first thing you can do to help your child is to educate yourself and seek out doctors who are knowledgeable about the disease and its management. An experienced medical team is your child's best chance to prevent or delay complications. Your family may also benefit from a visit with a genetic counselor.

Other tips for helping your child cope:

• Be honest when faced with questions about the disease, from your child or others. Your child will be reassured that you're at ease discussing it.
• Promote healthy self-esteem and body image from an early age by acknowledging your child's differences in a positive light. Also teach your child constructive ways to deal with teasing.
• Try to lead younger kids gently toward activities they won't have to give up later — for example, encourage music or computers over basketball. If your child is older when diagnosed and is forced to give up some favorite sports, encourage the development of other talents and interests.
• Keep in touch with teachers and explain that even though Marfan syndrome doesn't affect your child's intelligence, some modifications may be needed in class (such as letting your child sit near the board if vision is a problem).

Finding Safe Activities

• Talk to the P.E. teacher about safe vs. unsafe activities, and ask that your child be included even when he or she cannot compete (for example, if your child can't play in the soccer game, can he or she be the scorekeeper?).
• Encourage exercising. Staying active is important for everyone, even kids with Marfan syndrome, so ask your doctor for a list of appropriate activities.
• Above all, remember that kids need to be kids! Children with Marfan syndrome need to play and laugh and learn that there's so much more they can do than they can't.

If you or your child needs help adjusting to a diagnosis of Marfan syndrome, look for a support group near you or seek professional counseling.

When to Call the Doctor

Although aortic dissections are extremely rare in kids, call the doctor if your child has chest pain, shortness of breath (especially during exercise), an irregular pulse, sudden weakness or tingling in the legs and arms, or an unexplained fever. Also call the doctor if your child experiences any sudden vision changes.

Reviewed by: Karen W. Gripp, MD
Date reviewed: July 2011