|A service of the U.S. National Library of Medicine®|
On this page:
Reviewed March 2012
What is Marfan syndrome?
Marfan syndrome is a disorder that affects the connective tissue in many parts of the body. Connective tissue provides strength and flexibility to structures such as bones, ligaments, muscles, blood vessels, and heart valves. The signs and symptoms of Marfan syndrome vary widely in severity, timing of onset, and rate of progression.
The two primary features of Marfan syndrome are vision problems caused by a dislocated lens (ectopia lentis) in one or both eyes and defects in the large blood vessel that distributes blood from the heart to the rest of the body (the aorta). The aorta can weaken and stretch, which may lead to a bulge in the blood vessel wall (an aneurysm). Stretching 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.
Many people with Marfan syndrome have additional heart problems including a leak in the valve that connects two of the four chambers of the heart (mitral valve prolapse) or the valve that regulates blood flow from the heart into the aorta (aortic valve regurgitation). Leaks in these valves can cause shortness of breath, fatigue, and an irregular heartbeat felt as skipped or extra beats (palpitations).
Individuals with Marfan syndrome are usually tall and slender, have elongated fingers and toes (arachnodactyly), and have an arm span that exceeds their body height. Other common features include a long and narrow face, crowded teeth, an abnormal curvature of the spine (scoliosis or kyphosis), and either a sunken chest (pectus excavatum) or a protruding chest (pectus carinatum). Some individuals develop an abnormal accumulation of air in the chest cavity that can result in the collapse of a lung (spontaneous pneumothorax). A membrane called the dura, which surrounds the brain and spinal cord, can be abnormally enlarged (dural ectasia) in people with Marfan syndrome. Dural ectasia can cause pain in the back, abdomen, legs, or head. Most individuals with Marfan syndrome have some degree of nearsightedness (myopia). Clouding of the lens (cataract) may occur in mid-adulthood, and increased pressure within the eye (glaucoma) occurs more frequently in people with Marfan syndrome than in those without the condition.
The features of Marfan syndrome can become apparent anytime between infancy and adulthood. Depending on the onset and severity of signs and symptoms, Marfan can be fatal early in life; however, the majority of affected individuals survive into mid- to late adulthood.
How common is Marfan syndrome?
The incidence of Marfan syndrome is approximately 1 in 5,000 worldwide.
What genes are related to Marfan syndrome?
Mutations in the FBN1 gene cause Marfan syndrome. The FBN1 gene provides instructions for making a protein called fibrillin-1. Fibrillin-1 attaches (binds) to other fibrillin-1 proteins and other molecules to form threadlike filaments called microfibrils. Microfibrils become part of the fibers that provide strength and flexibility to connective tissue. Additionally, microfibrils store molecules called growth factors and release them at various times to control the growth and repair of tissues and organs throughout the body. A mutation in the FBN1 gene can reduce the amount of functional fibrillin-1 that is available to form microfibrils, which leads to decreased microfibril formation. As a result, excess growth factors are released and elasticity in many tissues is decreased, leading to overgrowth and instability of tissues.
Read more about the FBN1 gene.
How do people inherit Marfan syndrome?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
At least 25 percent of Marfan syndrome cases result from a new mutation in the FBN1 gene. These cases occur in people with no history of the disorder in their family.
Where can I find information about diagnosis or management of Marfan syndrome?
These resources address the diagnosis or management of Marfan syndrome and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about Marfan syndrome?
You may find the following resources about Marfan syndrome helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for Marfan syndrome?
What if I still have specific questions about Marfan syndrome?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding Marfan syndrome?
aneurysm ; aorta ; aortic dissection ; arachnodactyly ; autosomal ; autosomal dominant ; cataract ; cell ; connective tissue ; ectasia ; ectopia lentis ; gene ; glaucoma ; incidence ; inherited ; microfibrils ; mitral valve ; mitral valve prolapse ; mutation ; myopia ; nearsightedness ; new mutation ; palpitations ; pectus excavatum ; pneumothorax ; progression ; protein ; scoliosis ; spontaneous ; syndrome ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (15 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.