Marfan syndrome is a rare, inherited disorder of connective tissue and growth. The disease affects several parts of the body. The disease is highly variable, which means that different people with the condition will have different parts of their body affected to a greater or lesser degree.
The cause of the Marfan syndrome has been identified as a gene located on chromosome 15. This gene encodes a specialized protein called “fibrillin” that contributes to the production of normally functioning connective tissue in our body. In Marfan syndrome, a mutation of the fibrillin gene is present in the majority of patients (75-90%). There may be slight variations or mutations in the fibrillin gene, which can produce similar findings in all patients. Unrelated patients or families appear to have different mutations in the fibrillin gene.
Marfan syndrome has an incidence rate of 1 per 5,000 individuals. Approximately 80% of patients with Marfan syndrome will have a positive family history, which is one major criterion of the syndrome. This requires a very specific diagnosis of the syndrome in other family members, not just someone who is unusually tall. In the rest of the patients, the syndrome results from a new mutation not present in other family members.
Marfan syndrome is inherited in an autosomal dominant manner. The term autosomal means that men and women are equally likely to inherit and/or pass on the condition. Dominant conditions typically affect individuals in every generation. If an individual has an autosomal dominant condition like Marfan syndrome, they have a 50% or 1 in 2 chance of passing the condition on to each of their children. Because of the variable expression of the Marfan gene, it is not possible to predict how severely a child who inherits the gene will be affected.
The features of Marfan syndrome result from changes in the body’s connective tissue and in the control of body growth. Connective tissue holds our bodies together. It is found throughout the body, which is why it can affect many different parts of the body.
Marfan syndrome most commonly affects the heart and blood vessels, the bones and joints and the eyes. It can also affect the lungs and the skin. The number and type of features that are present can vary a lot between different people with Marfan syndrome. Some will have only a few features, while others will have many.
The most common and serious feature of Marfan syndrome is dilation or widening of the aorta, which is the main blood vessel that carries blood out of the heart to the rest of the body. The dilation can progress until the wall of the aorta tears, a condition called aortic dissection. This is the most serious or life-threatening feature of Marfan syndrome. However, aortic dissection can be avoided by taking appropriate medicine and with preventive surgery to replace a dilated aorta, before it tears.
Since Marfan syndrome is partly caused by changes in growth regulation, people with the disorder can often have some of the following traits:
- They are taller than people in their family who do not have Marfan syndrome
- They may have long, thin fingers and long arms and legs
- They may have a dislocation of the lens in the eye that also causes nearsightedness or myopia that can progress quickly
- They may have a detached retina, early glaucoma or early cataracts
There is no cure for Marfan syndrome, but life expectancy has increased significantly over the last few decades. The syndrome is treated by addressing each issue as it arises, and, in particular, considering preventive medication, even for young children.
Regular checkups by a cardiologist are recommended to monitor the health of the heart valves and the aorta. The goal of treatment is to slow the progression of aortic dilation and damage to heart valves by eliminating arrythmias, minimizing the heart rate, and minimizing blood pressure.
Patients with an enlarged aorta will be advised against participating in any high impact or high isometric or static activities, such as weight lifting, football, basketball, etc. These activities can cause sudden excessive enlargement of the aorta leading to tearing or possible rupture. If the aortic valve begins to leak or if the aorta begins to enlarge excessively, surgical intervention by repairing or replacing either the valve or the enlarged aorta may be necessary.
Skeletal abnormalities need to be evaluated by general surgeons or orthopedic surgeons who are experienced in the skeletal deformities, since many of the skeletal changes may require specialized surgery to correct them. Various surgical procedures can stabilize the spine if there is significant spinal deformity, and techniques are available to correct severe depression of the breast bone.
The major problem with the eyes is dislocation of the lenses. In most patients, dislocation of the lens is a minor problem. Dislocated lenses often interfere with vision and may require special eyeglasses or contact lenses. On rare occasions the lens may have to be removed. Because of the increased risk of retinal detachments, activities that involve blows to the head such as football, boxing and diving should be avoided.
Because of the risk of lung collapse (pneumothorax), Marfan syndrome patients should not subject themselves to extremes of air pressure or rapid changes in pressure. For example, Marfan syndrome patients should avoid riding in unpressurized aircraft or diving under water more than several feet.