Genetics Northern California

Marfan syndrome

What is Marfan syndrome?
How common is Marfan syndrome?
What causes Marfan syndrome?
How is Marfan syndrome diagnosed?
How is Marfan syndrome treated?
Where can I get more information about Marfan syndrome?

What is Marfan syndrome?
Marfan syndrome is a type of connective tissue disorder. Connective tissue gives strength and flexibility to many parts of the body. In Marfan syndrome, the connective tissue does not work in the normal way. This can affect bones, joints, eyes, blood vessels, heart, and other organs. Marfan syndrome is variable, which means that individuals with Marfan syndrome may not have exactly the same features, even if they are in the same family.

The most common body parts affected by Marfan syndrome are the bones, joints, eyes, blood vessels, and heart.
Bones and joints: People with Marfan syndrome are often taller than average. They can have long, thin fingers and long faces. They sometimes have curving of the spine (scoliosis) and may have a chest that seems to stick out or cave in. Loose joints are also common.

Eyes: Near-sightedness (myopia) is common in Marfan syndrome, but many people without Marfan syndrome also have myopia. Sometimes the lens of the eye can shift out of place because the connective tissue is looser than usual. This is called ectopia lentis. It is considered a hallmark feature of Marfan syndrome because it does not usually happen to someone without this condition.

Blood vessels and heart: The blood vessels and heart can be affected in different ways. Many people with Marfan syndrome have a heart valve that does not close properly (mitral valve prolapse or tricuspid valve prolapse). In most cases, this does not cause serious medical problems. The looser connective tissue in Marfan syndrome may also lead to gradual stretching (enlargement) of the aorta. The aorta is the large artery that carries blood out of the heart into the body. Stretching the aorta too far can cause this blood vessel to break open, which is life-threatening.

Other features are sometimes seen in people with Marfan syndrome, such as, recurrent hernias and pneumothorax (collapsed lung). People with Marfan syndrome typically have normal intelligence.

How common is Marfan syndrome?
Marfan syndrome affects about 1 in 5,000 people. It affects both males and females of all racial and ethnic backgrounds.

What causes Marfan syndrome?
Marfan syndrome is caused by a genetic change (mutation) in a gene called fibrillin-1 (FBN1). It is an autosomal dominant condition, which means that a mutation in just one copy of the FBN1 gene can cause Marfan syndrome. Rarely, a mutation in a different gene, such as TGFBR1 or TGFBR2, may also cause Marfan syndrome. Most people who have Marfan syndrome have one parent who has Marfan syndrome. In some cases, the parent may be unaware that they have the condition. Other times, there is no one else in the family with Marfan syndrome. About 1 in 4 people with Marfan syndrome are the first person in the family to have the condition due to a de novo (brand new) mutation in the FBN1 gene. Any person who has Marfan syndrome can pass the condition to their children. Each child of a parent with Marfan syndrome has a 50% chance of inheriting the condition.

How is Marfan syndrome diagnosed?
Marfan syndrome is usually diagnosed in a genetics clinic by reviewing the family history and performing a specialized physical exam. There are specific criteria that doctors use to decide if a person has Marfan syndrome. Genetic testing is generally not needed to make a diagnosis.
Genetic Testing
Genetic testing may be useful in some situations. Most people with Marfan syndrome have a detectable mutation in the fibrillin-1gene (FBN1). However, a person can still have Marfan syndrome even with a negative genetic test (no mutation found). Genetic testing may also include other genes that cause conditions similar to Marfan syndrome. Diagnostic testing is available during pregnancy when a parent’s gene mutation is known.

How is Marfan syndrome treated?
Treatment for Marfan syndrome focuses on specialized care for symptoms related to the condition. Regular monitoring by a heart doctor (cardiologist) is important. Medications are often used to slow or prevent enlargement of the aorta. Surgery is recommended when the aorta gets too large, to prevent it from breaking open (rupture or dissection). There may also be the need for regular appointments with a specialized eye doctor (ophthalmologist) and an orthopedist. The American Academy of Pediatricians (AAP) has established medical care guidelines for children with Marfan syndrome. There are also guidelines for adults.

Some physical activities can raise the risk for blood vessel or eye problems. People with Marfan syndrome are advised to avoid contact sports, such as football or wrestling. They should also avoid weight lifting and scuba diving. However, someone with Marfan syndrome can participate in non-contact sports, such as swimming. You can speak with your doctor for advice on appropriate physical activities for people with Marfan syndrome.

Where can I get more information about Marfan syndrome?
NIH: Genetics Home Reference on Marfan syndrome: General information about Marfan syndrome provided as a service of the U.S. National Library of Health. Links to many related sites are included on the page.
Gene Reviews on Marfan Syndrome: Detailed information about Marfan syndrome intended for medical professionals.

Family Support Resources
The Marfan Foundation - www.marfan.org


Last reviewed: February 2, 2018
Reviewed by: Kimberly Barr, MS, LCGC