Marfan Syndrome

What causes Marfan syndrome?

Marfan syndrome is caused by an abnormality (or mutation) in one specific gene (FBN1). Up to 75 percent of the time, this mutated gene is inherited from a parent who is affected.

Nearly 25 percent of the time, cases are thought to be caused by new mutations in the family (not inherited from a parent). Scientists have noted that offspring of fathers who are older (than the norm) at the time of conception may be affected by this gene mutation more often than others. Mutations occur sporadically (by chance) in the sperm of older men (over 45 years) who father children at a rate of 1 percent. These "point mutations" can result in Marfan syndrome, or other disorders, depending on which gene is accidentally altered.

Marfan syndrome is an autosomal dominant disorder. This means that each offspring of an affected parent will have a 50 percent chance of also being born with the disorder. Similarly, when a child is born with Marfan syndrome to unaffected parents, the child will have a 50 percent risk of passing the gene on to the next generation.

Why is Marfan syndrome a concern?

Children with Marfan syndrome are at risk for serious problems involving the cardiovascular system, including the following:

• mitral valve prolapse - an abnormality of the valve between the left atrium and left ventricle of the heart that causes backward flow of blood from the left ventricle into the left atrium.
• arrhythmia (or dysrhythmia) - a fast, slow, or irregular heartbeat.
• aortic regurgitation - backwards leakage of blood from the aorta, through a weakened aortic valve, and into the left ventricle, resulting in stress in the left heart and inadequate blood flow to the body.
• aortic dissection - weakening of the layers inside the aorta, which can result in tears in the aortic wall and leakage of blood into the chest or abdomen; a medical emergency.

What are the symptoms of Marfan syndrome?

A deficiency of fibrillin in connective tissue creates the abnormalities in organs and body structures that may be seen with Marfan syndrome. An extensive list of abnormalities can occur with the disorder; only symptoms listed as "major criteria" are listed below. Other symptoms may be noted that contribute to the certainty of the diagnosis. Each child may experience symptoms differently. Symptoms may include:

• heart and blood vessels
  • dilation of the aorta
  • leakage of the aortic valve (aortic regurgitation)
  • tears in the aorta (aortic dissection)
• skeletal
  • deformities of the breastbone
  • scoliosis - a lateral, or sideways curvature and rotation of the back bones (vertebrae), giving the appearance that the person is leaning to one side.
  • misalignment of certain bones
  • joint contractures
  • unusual arm span
  • long fingers and toes
• eye
  • dislocation of the lens (the transparent structure inside the eye that focuses light rays onto the retina)

The symptoms of Marfan syndrome may resemble other problems or medical conditions. Always consult your child's physician for a diagnosis.

How is Marfan syndrome diagnosed?

In addition to a complete medical history and physical examination, your child's physician may complete a family medical history to look for other family members with known Marfan syndrome or some of the characteristics of the disease.

Other diagnostic tests for Marfan syndrome may include the following:

• electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
• echocardiography (echo) - a procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
• complete eye examination - an examination of the interior of the eye, performed by an ophthalmologist, using a device called a slit lamp.
• x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
• DNA studies - a blood sample sent to the genetics lab can analyze the FBN1 gene to determine whether a mutation is present; not all mutations in the fibrillin gene cause Marfan syndrome. Similarly, not all persons with Marfan syndrome have a mutation in this gene. Sometimes, a type of DNA study called a linkage study, which examines the DNA of several family members, can aid in tracking the gene in the family. However, because of these limitations, the diagnosis of Marfan syndrome is primarily based on clinical findings.

In order to be diagnosed with Marfan syndrome, your child must exhibit several characteristics from a detailed list. Your child needs to have a significant number of the symptoms on the checklist in order to be diagnosed with the disorder. Your child's physician will make the diagnosis based on medical and family history and other factors, as well as symptoms your child may exhibit.

Marfan syndrome may be easier to diagnose as children age, as many of the features of the disorder become more obvious as your child grows.

Treatment for Marfan syndrome:

Specific treatment for Marfan syndrome will be determined by your child's physician based on:

• your child's age, overall health, and medical history
• extent of the disorder
• your child's tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

At the present time, there is no cure for the disorder. Treatment is based on determining which organ systems are affected and managing the problems that arise. Recommendations for managing Marfan syndrome may include the following:

• an annual echocardiogram, or echo (to monitor the heart and aorta)
• periodic eye examination by an ophthalmologist
• monitoring of the skeletal system for abnormalities (such as scoliosis) that can be noted in childhood or adolescence
• lifestyle adjustments (to reduce the risk of injury to the aorta, such as avoiding contact sports or stressful exercise)
• the use of antibiotics before dental procedures (to reduce the chance of developing a heart infection)

Genetic counseling is important for people who have Marfan syndrome and are planning to have a family. If one parent has the disorder, there is a 50 percent chance, with each pregnancy, for a child to also have Marfan syndrome. In addition, women with Marfan syndrome who become pregnant have significant risks for their health during pregnancy, due to the added stress that a pregnancy puts on the heart. Avoidance of pregnancy is often recommended to reduce the risk of injury to the aorta.

Long-term outlook for a child with Marfan syndrome:

Heart and blood vessel problems pose the largest threat to a person with Marfan syndrome, which emphasizes the importance of regular evaluation by your child's physician. Consult your child's physician for more information regarding the specific outlook for your child. With advances in the diagnosis, evaluation, and management of the organ abnormalities associated with Marfan syndrome, the life expectancy for a person with the disease has nearly doubled in the past 25 years. Today, individuals with Marfan syndrome can expect to live about 70 years. For women with Marfan syndrome, pregnancy and childbirth pose significant risks. These women should be evaluated with echocardiography prior to becoming pregnant. Other diagnostic imaging procedures, such as computed tomography angiography (CTA) or magnetic resonance angiography (MRA), may be used to assess risks. Cesarean delivery (C-section) is generally recommended for pregnant women with Marfan syndrome to prevent strain on the aorta and decrease the risk of aortic dissection during labor. Click here to view the Online Resources of Cardiovascular Disorders.

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Online Resources of Cardiovascular Disorders