Marfan syndrome is a condition in which your body's connective tissue is abnormal. Connective tissue helps support all parts of your body. It also helps control how your body grows and develops.

Marfan syndrome most often affects the connective tissue of the heart and blood vessels, eyes, bones, lungs, and covering of the spinal cord. Because the condition affects many parts of the body, it can cause a number of complications. In some cases, the complications are life threatening.


Marfan syndrome is a genetic disorder. A mutation, or change, in the gene that controls how the body makes fibrillin causes Marfan syndrome. Fibrillin is a protein that plays a major role in your body's connective tissue.

Most people who have Marfan syndrome inherit it from their parents. If you have Marfan syndrome, you have a 50 percent chance of passing the altered gene on to each of your children. In about 1 in 4 cases, Marfan syndrome occurs because of a spontaneous mutation. Thus, the affected person is the first in their family to have the condition.

Marfan syndrome often affects the long bones of the body. This can lead to signs, or traits, such as:

  • A tall, thin build.
  • Long arms, legs, fingers, and toes and flexible joints.
  • A spine that curves to one side. This condition is called scoliosis (sko-le-O-sis).
  • A chest that sinks in or sticks out. These conditions are called pectus excavatum (eks-ka-VA-tum) and pectus carinatum (ka-ri-NA-tum).
  • Teeth that are too crowded.
  • Flat feet.

Marfan syndrome traits vary from person to person, even in the same family. Some people who have the condition have many traits, while others have few.

Cardiac and Vascular Complications

The most serious complications of Marfan syndrome involve the heart and blood vessels. Most people with Marfan syndrome have abnormalities of the heart and the aorta. Marfan syndrome can affect the aorta, the main blood vessel that supplies oxygen-rich blood to the body. In Marfan syndrome, the aorta can weaken and stretch. This condition is called aortic dilation or aortic aneurysm (AN-u-rism).

Leaks in valves that control blood flow through the heart can cause shortness of breath, fatigue, and an irregular heartbeat felt as skipped or extra beats (palpitations). If leakage occurs, it usually affects the mitral valve, which is a valve between two chambers of the heart, or the aortic valve that regulates blood flow from the heart into the aorta. The first few inches of the aorta can weaken and stretch, which may lead to a bulge in the blood vessel wall (an aneurysm). The increased size of the aorta may cause the aortic valve to leak, which can lead to a sudden tearing of the layers in the aorta wall (aortic dissection). Aortic aneurysm and dissection can be life threatening.

Marfan syndrome has no cure, but treatments can help delay or prevent complications of the condition. Treatments include medicines, surgery, and other therapies. Limits or changes to certain activities may help reduce the risks to the aorta, eyes, and joints.

The type of treatment you receive depends on how the condition is affecting your body.


About 1 out of every 5,000 people in the United States has Marfan syndrome. Men, women, children, and people of all races can have the condition.

New advances have been made in the early diagnosis and treatment of Marfan syndrome. It's now possible for people who have Marfan syndrome to live longer and enjoy a good quality of life. Many people who have Marfan syndrome and are properly diagnosed and treated may live an average lifespan.

Researchers continue to study the condition and look for better treatments.