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 many complications. Sometimes the complications are life threatening.
                
Overview
                
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 to each of your children.
                
In about 1 in 4 cases, the mutation that causes Marfan syndrome is not inherited. Thus, the affected person is the first in his or her 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), respectively.
                
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.
                
The most serious complications of Marfan syndrome involve the heart and blood vessels. Marfan syndrome can affect the aorta, the main blood vessel that supplies oxygen-rich blood to the body. In Marfan syndrome, the aorta can stretch and grow weak. This condition is called aortic dilation (di-LA-shun) or aortic aneurysm (AN-u-rism).
                
If the aorta stretches and grows weak, it may tear or burst and leak blood. This condition is called aortic dissection. It's very serious and can lead to severe heart problems or even death.
                
Marfan syndrome has no cure, but treatments can help delay or prevent complications. Treatments include medicines, surgery, and other therapies. Limiting certain activities, or changing how you do them, 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.
                
Outlook
                
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.
                
Advances have been made in the early diagnosis and treatment of Marfan syndrome. It's now possible for people who have the condition 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.