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Marfan syndrome
Definition
Marfan syndrome is a disorder of connective tissue, the tissue that strengthens the body's structures.
Disorders of connective tissue affect the skeletal system, cardiovascular system, eyes, and skin.
Causes
Marfan syndrome is caused by defects in a gene called fibrillin-1. Fibrillin-1 plays an important role as the building block for connective tissue in the body.
The gene defect also causes too much growth of the long bones of the body. This causes the tall height and long arms and legs seen in people with this syndrome. How this overgrowth happens is not well understood.
Other areas of the body that are affected include:
- Lung tissue (there may be a pneumothorax, in which air can escape from the lung into the chest cavity and collapse the lung)
- The aorta, the main blood vessel that takes blood from the heart to the body may stretch or become weak (called aortic dilation or aortic aneurysm)
- The eyes, causing cataracts and other problems (such as a dislocation of the lenses)
- The skin
- Tissue covering the spinal cord
In most cases, Marfan syndrome is inherited, which means it is passed down through families. However, up to 30% of patients have no family history, which is called "sporadic." In sporadic cases, the syndrome is believed to be caused by a new gene change.
Symptoms
People with Marfan syndrome are usually tall with long, thin arms and legs and spider-like fingers -- called arachnodactyly. When they stretch out their arms, the length of their arms is greater than their height.
Other symptoms include:
- A chest that sinks in or sticks out -- funnel chest (pectus excavatum) or pigeon breast (pectus carinatum)
- Flat feet
- Highly arched palate and crowded teeth
- Hypotonia
- Joints that are too flexible (but the elbows may be less flexible)
- Learning disability
- Movement of the lens of the eye from its normal position (dislocation)
- Nearsightedness
- Small lower jaw (micrognathia)
- Spine that curves to one side (scoliosis)
- Thin, narrow face
Exams and Tests
The doctor will perform a physical exam. There may be hypermobile joints and signs of:
- Aneurysm
- Collapsed lung
- Heart valve problems
An eye exam may show:
- Defects of the lens or cornea
- Retinal detachment
- Vision problems
The following tests may be performed:
- Echocardiogram
- Fibrillin-1 mutation testing (in some people)
An echocardiogram should be done every year to look at the base of the aorta.
Treatment
Vision problems should be treated when possible.
Monitor for scoliosis, especially during the teenage years.
Medicine to slow the heart rate may help prevent stress on the aorta. Avoid participating in contact sports to avoid injuring the aorta of the heart. Some people may need surgery to replace the aortic root and valve.
People with Marfan syndrome who have heart valve conditions should take antibiotics before dental procedures to prevent endocarditis. Pregnant women with Marfan syndrome must be monitored very closely because of the increased stress on the heart and aorta.
Support Groups
National Marfan Foundation -- www.marfan.org
Outlook (Prognosis)
Heart-related complications may shorten the lifespan of people with this disease. However, many patients survive well into their 60s. Good care and surgery may extend the lifespan further.
Possible Complications
Complications may include:
- Aortic regurgitation
- Aortic rupture
- Bacterial endocarditis
- Dissecting aortic aneurysm
- Enlargement of the base of the aorta
- Heart failure
- Mitral valve prolapse
- Scoliosis
- Vision problems
When to Contact a Medical Professional
Experts recommend genetic counseling for couples with a history of this syndrome who wish to have children.
Prevention
Spontaneous new gene mutations leading to Marfan (less than 1/3 of cases) cannot be prevented. If you have Marfan syndrome, see your doctor at least once every year.
References
Pyeritz RE. Inherited diseases of connective tissue. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 268.
Doyle J, Dietz III H. Marfan syndrome. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 693.
Reviewed By: Chad Haldeman-Englert, MD, Wake Forest University School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
