The protein that plays a role in Marfan syndrome is called fibrillin-1. Marfan syndrome is caused by a defect (or mutation) in the gene that tells the body how to make fibrillin-1. This mutation results in an increase in a protein called transforming growth factor beta. The increase causes problems in connective tissues throughout the body, which in turn creates the features and medical problems associated with Marfan syndrome and some related conditions.
Features of the disorder are most often found in the heart, blood vessels, bones, joints, and eyes. Some Marfan features – for example, aortic enlargement (expansion of the main blood vessel that carries blood away from the heart to the rest of the body) – can be life-threatening. The lungs, skin and nervous system may also be affected. Marfan syndrome does not affect intelligence.
WHO IS AFFECTED? About 1 in 5,000 people have Marfan syndrome, including men and women of all races and ethnic groups. About 3 out of 4 people with Marfan syndrome inherit it, meaning they get the genetic mutation from a parent who has it. But some people with Marfan syndrome are the first in their family to have it; when this happens it is called a spontaneous mutation. There is a 50 percent chance that a person with Marfan syndrome will pass along the genetic mutation each time they have a child.
WHAT ARE THE FEATURES? Some people have many features at birth or as young children. Other people develop features, including aortic enlargement, as teens or even as adults. Some features are progressive, meaning they can get worse as people age. All of this makes it very important for people with Marfan syndrome and related conditions to have ongoing monitoring, especially for life-threatening aspects of the condition like aortic enlargement. An accurate and early diagnosis helps to ensure proper treatment. Some treatments can prevent symptoms from getting worse and ultimately save lives.
Every person’s experience with Marfan syndrome is slightly different. No one has every feature and people have different combinations of features. Some features of Marfan syndrome are easier to see than others. These include:
Long arms, legs and fingers
Tall and thin body type
Curved spine
Chest sinks in or sticks out
Flexible joints
Flat feet
Crowded teeth
Stretch marks on the skin that are not related to weight gain or loss
Harder-to-detect signs of Marfan syndrome include heart problems, especially those related to the aorta, the large blood vessel that carries blood away from the heart to the rest of the body. Other signs can include sudden lung collapse and eye problems, including severe nearsightedness, dislocated lens, detached retina, early glaucoma, and early cataracts. Special tests are often needed to detect these features.