Marfan Syndrome

Marfan syndrome involves the body's connective tissue and is characterized by abnormalities in the skeleton, heart, and eyes. It is caused by an abnormal gene ^* that usually is inherited. People with Marfan syndrome are generally taller than average, have little body fat, and have long: thin fingers.

What Is Marfan Syndrome?

Marfan syndrome was first described in 1896 by the French physician Antonine Marfan. Some famous people of the past, such as Abraham Lincoln, who was very tall and lanky, and the brilliant violinist Niccolo Paganini, who had very long fingers, are believed by some to have had Marfan syndrome. Today, the disorder has received attention in the media largely as a result of health problems and deaths among very tall athletes, such as some basketball and volleyball players. Still, the disorder is rare.

Marfan syndrome affects only about 1 to 2 persons of every 10,000. In the United States, it has been estimated that 40,000 or more people have the disorder. It affects men and women in equal numbers, as well as people of all racial and ethnic groups. Marfan syndrome can affect the heart and aorta ^* , the eyes, and the skeleton.

What Causes Marfan Syndrome?

For many years, it had been known that Marfan syndrome was inherited. It had been observed that if someone had the disorder, each of his or her children would have about a 50 percent chance of developing it as well. However, it was not known what gene or genes were responsible for the disorder.

Then, in the early 1990s, researchers found that the condition is caused by a single abnormal gene. This gene is involved in the production of a type of protein, called fibrillin, which gives connective tissue its strength. Connective tissue is the material that holds in place all the structures of the body. When the gene is defective, it causes critical changes in fibrillin that may weaken and loosen the connective tissue. This effect, in turn, causes the wide range of features, such as tall stature and loose joints, that are found in Marfan syndrome. It is not as yet known just how alterations in the genes produce these features.

Although anyone born to a parent with Marfan syndrome has a 50-50 chance of inheriting the disorder, an estimated 25 percent of people with Marfan syndrome do not have a parent who has it. This is because a person can have the defective gene owing to a spontaneous mutation, or change, in the normal gene.

What Are the Signs and Symptoms of Marfan Syndrome?

The characteristic signs and symptoms of Marfan syndrome usually do not begin to become apparent until about age 10. When they do emerge, they may involve any or all of three parts of the body: the skeleton, the circulatory system (heart and blood vessels), and the eyes.

The Skeleton

A person who has Marfan syndrome usually (but not always) grows to be very tall and thin. The fingers also tend to be long and thin, or "spidery." The head is sometimes elongated too, and the chest may have a caved-in look. The joints tend to be supple and loose, and are prone to becoming dislocated. Sometimes there may be scoliosis (sko-lee-O-sis), a side-to-side curvature of the spine.

The Circulatory System

The most serious features of Marfan syndrome involve the heart and aorta, the main artery that carries blood directly from the heart to the body. A characteristic defect in one of the valves of the heart (mitral valve) can cause irregular heart rhythm. Weakness in the aorta can allow it to widen, eventually leading to the development of an aneurysm (AN-yoo-riz-um), a weakness or bulge. If undiscovered or untreated, the weak spot in the aorta can rupture, causing severe internal hemorrhage and death, without warning.

The Eyes

A common symptom of Marfan syndrome is myopia (my-O-pee-uh), or nearsightedness. In addition, in about half of individuals with the disorder, there is dislocation of the lens of the eye, which can make cataracts (clouding of the lens of the eye) more likely to develop.

How Is Marfan Syndrome Diagnosed?

Marfan syndrome can be difficult to diagnose. As yet no single laboratory test can identify it. Some people with the condition do not have all of its characteristic signs. Conversely, most people who are tall, lanky, and nearsighted do not have Marfan syndrome. (Again, the disorder is rare.)

Accurate diagnosis is made from a combination of one's family history and a complete physical examination that focuses on the skeleton, heart and aorta, and the eyes. An echocardiogram (ek-o-KAR-de-o-gram), a picture of the heart produced by using sound waves, can detect abnormalities in the heart and aorta. Eye doctors can look for possible lens dislocations.

The recent identification of the gene that causes Marfan syndrome, and of fibrillin as the component of connective tissue affected by the gene, will likely aid in future diagnosis.

How Is Marfan Syndrome Treated and Prevented?

Treatment and prevention of complications depend upon the individual symptoms of the person affected by the syndrome. Main aspects include annual echocardiograms to watch for enlargement of the aorta and to monitor heart function, and continuing eye examinations to detect lens dislocation. Medications called beta-blockers may be prescribed to lower blood pressure to help prevent aneurysms from developing in the aorta. Braces can be used to correct spinal curvature.

In terms of lifestyle, strenuous sports may have to be avoided to reduce the risk of damage to the aorta. Genetic counseling is advisable for anyone thinking about having children, because of the risk that children will inherit the condition. Although there is no cure for Marfan syndrome, working closely with one's doctor in an ongoing monitoring and treatment program can greatly improve the outlook for long life.