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 the condition, you have a 50 percent chance of passing the altered gene to each of your children.
Sometimes Marfan syndrome isn't inherited. The mutation in the fibrillin gene occurs in the egg or sperm cells. If a child is conceived, the altered gene may be passed on to the child. The risk of that child's brothers or sisters having Marfan syndrome is low.
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.