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Marfan Syndrome

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Overview

What is Marfan syndrome? The following text is taken from the Genetics Home Reference (update pending):

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.

Because connective tissue is found throughout the body, Marfan syndrome can affect many systems, often causing abnormalities in the heart, blood vessels, eyes, bones, and joints. 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), loose joints, 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), stretch marks (striae) not related to weight gain or loss, 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 syndrome can be fatal early in life; however, with proper treatment, many affected individuals have normal lifespans.

Frequency
The incidence of Marfan syndrome is approximately 1 in 5,000 worldwide.

Causes
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 bind to 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, microfibrils cannot bind to growth factors, so excess growth factors are available and elasticity in many tissues is decreased, leading to overgrowth and instability of tissues in Marfan syndrome.

Inheritance Pattern
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.

Resources

We are compiling a list of websites to help you understand genetics and genetic test results. If you would like to suggest other resources for this section, please feel free to This email address is being protected from spambots. You need JavaScript enabled to view it.!
INFORMATION ABOUT GENETICS AND GENETIC TESTING:

Weblink to Genetics Home Reference Genetics Home Reference
Consumer-friendly information about the effects of genetic variations on human health. Federally-supported resources, include reviews of more than 800 genetic diseases and more than 1000 genes.


Weblink to NHGRI Learning ResourcesLearning Resources from the NHGRI
Lots of very good resources from the NHGRI, including major sections about The Human Genome Project, Facts Sheets, and educational resources for teachers and students.


Weblink to National Society of Genetic CounselorsFind a Genetic Counselor
The National Society of Genetic Counselors have a searchable database of genetic counselors. Their website also includes some education materials for patients and healthcare professionals.


Weblink to NHGRI Talking GlossaryNHGRI Talking Glossary
Talking glossary of genetic terms developed by the National Human Genome Research Institute. A huge range of definitions is provided by researchers from around the world.


Weblink to Help Me Understand GeneticsHelp Me Understand Genetics
Help Me Understand Genetics is a handbook from the National Institutes of Health that contain useful information about genetics in clear language and provides links to even more online resources. The entire handbook can also be downloaded as a pdf.


Weblink to the Genetic and Rare Diseases Information CenterGenetic and Rare Diseases Information Center (GARD)
A joint project from The Office of Rare Diseases Research (ORDR) and the National Human Genome Research Institute (NHGRI) that provides searchable information about genetic conditions and rare diseases. It also includes a list of FDA-Approved drugs and other medical products for treating rare disease.


Weblink to NORDNational Organization for Rare Disorders - Resources for Parents/Families
The National Organization for Rare Disorders (NORD) is a volunteer organization dedicated to empowering the rare disease community. Again, they have some very nice web resources.


Weblink to ELSIEthical, Legal and Social Implications Research Program
The ELSI Research Program supports examinations and investigations of the ethical, legal and social implications of genetics research.


Weblink to GINAGenetic Information Nondiscrimination Act of 2008
The Genetic Information Nondiscrimination Act of 2008, also referred to as GINA, is a new federal law that protects Americans from being treated unfairly because of differences in their DNA that may affect their health.


Weblink to Learn.GeneticsLearn.Genetics, University of Utah
Excellent resources, especially for those involved in education. Includes a catalog of animations, videos, interactive features, and virtual labs.


Weblink to the Dolan DNA Learning CenterDolan DNA Leaning Center
The DNALC provides genetics learning resources for teachers and students.


INFORMATION FOR RESEARCHERS:

Weblink to the ClinVar ACMG recommendations pageClinVar: ACMG Recommendations for Reporting of Incidental Findings in Clinical Exome and Genome Sequencing
Clinvar's dedicated ACMG page - a useful jumping-off point to the Genetic Testing Registry, OMIM, MedGen, and local ClinVar pages for each gene.


Weblink to NCBI GeneReviews General pageGene Reviews
Gene Reviews (updated September, 2018)


About

What is the purpose of this information?
Our aim is to provide information about why we do genetic testing. We try to answer some common questions and offer guidance on some personal and practical issues. This information is for anybody with questions about genetic testing for any of the diseases and drugs listed in this site.

Are there geographical differences in testing, service or treatment?
Different centers have different policies in terms of how tests are administered and results shared. However, the results discussed in this document should be relevant to most individuals tested for risk of developing genetic disease.

How is this paid for?
If you received this test as part of the eMERGE research study, neither you nor your insurance company will have to pay anything toward this test

When was this content last updated?
October 10, 2018.

More Questions? The National Society of Genetic Counselors has developed a directory to help locate genetic counseling services near you.
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