The Marfan syndrome is a heritable disorder of the connective tissue that affects many organ systems, including the skeleton, lungs, eyes, heart and blood vessels. All these seemingly unrelated characteristics are caused by a mutation in a single gene on Chromosome 15. This gene is named FBN1 for the protein it encodes, fibrillin-1. The precise order of A’s, C’s, G’s, and T’s in the gene determines the composition of the protein. The cell’s protein-production machinery reads the code in the gene and then adds the proper amino acid to the growing protein. Each amino acid is embodied by a different three-letter code. The gene produces many copies of the fibrillin protein and these join together to form a long stringy structure called a microfibril. But when one of these three letter codes get mixed up, then the machinery produces the wrong kind of amino acid and the microfibril gets deformed into a Marfan-infected one. Usually, this gene is inherited from a parent who is also affected. Approximately one-quarter of the cases occur because of a spontaneous mutation.
The Marfan syndrome is autosomal dominant, indicating that someone with the condition has a 50-50 chance that any offspring will inherit it.
The most serious problems that Marfan syndrome can cause involve the cardiovascular system. The two flaps in the mitral valve may turn backwards when the heart contracts. This can lead to leakage of the mitral valve or irregular heart rhythm.
In addition, the aorta, the main artery carrying blood away from the heart, is generally wider and more fragile in patients with the Marfan syndrome. This widening is progressive and can cause leakage of the aortic valve or tears in the aorta wall. When the aorta becomes very wide, or tears, surgical repair is necessary.
Skeletal signs common in people with the Marfan syndrome include scoliosis, abnormally shaped chest, loose joints and disproportionate growth usually, but not always, resulting in tall stature.
People with the Marfan syndrome are often near-sighted. In addition, about 50 percent have dislocation of the ocular lens.
The Marfan syndrome is difficult to diagnose because there is no specific laboratory test for the condition. In addition, characteristics of the disorder vary greatly among affected individuals. Most affected people do not have all of the possible signs and complications of the syndrome.
An accurate diagnosis of the Marfan syndrome can be assessed after a complete physical examination that focuses on the systems affected by the disorder. This will include an echocardiogram, a sound wave picture of the heart by a cardiologist, a slit-lamp eye examination by an ophthalmologist, a skeletal examination by an orthopedist, and a complete family history.
The identification in 1991 of the chromosome, gene and component of connective tissue (fibrillin) in which the mutation for the Marfan syndrome is located offers great promise for the diagnosis of the condition. It is hoped that as a better understanding of fibrillin is gained, earlier and more accurate diagnosis of the Marfan syndrome will be possible. People affected by the Marfan syndrome should be treated by a physician familiar with the condition and how it affects all body systems. There is no cure for the disorder yet, but careful medical management can greatly improve the prognosis and lengthen the life span.
Every affected person should work closely with his/her physician(s) for their customized treatment plan. However, in general, treatment includes the following:
Annual echocardiogram to monitor the size and function of the heart and aorta.
Initial eye examination with a slit-lamp to detect lens dislocation, with periodic follow-up with an ophthalmologist.
Careful monitoring of the skeletal system, especially during childhood and adolescence.
Beta-blocker medications may be prescribed to lower blood pressure and, consequently, reduce stress on the aorta.
This is usually surprising to most people, but the health of your heart depends on the health of your teeth, much more than you would think. That is why they need to take antibiotics by injection before they go to the dentist and in other situations in which bacteria could enter the blood stream.
People with Marfan syndrome should adapt to doing many different sports and outdoor activities to reduce the risk of injury to the aorta.
The Marfan syndrome is, again, a one-gene disorder on chromosome 15, causes injury to heart, skeleton, and eyes alike, does not have a cure yet may be diagnosed and treated, and a person has a 50/50 chance of getting it if one of his/her parents have it. This, as all other inherited sicknesses, is not contagious, so one should not be afraid of people that have it, but rather help them, if they need it.
Bibliography
“Marfan Syndrome” http://www.yourgenesyourhealth.org/ygyh/mason/ygyh.html?syndrome=marfan§ion=cause&video=0 - 2002.
“National Marfan Foundation: Fact Sheet” http://www.marfan.org/pub/factsheet.html -November 2002
Phillip Friedman “The New Book Of Knowledge: M”
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