What is Marfan syndrome?

Marfan syndrome is a disorder involving the body's connective tissue. Connective tissue has many important functions, including the following:

  • Assisting with growth and development of the body's cells, both before and after birth

  • Supporting tissues in the body

  • Acting as an adhesive to hold certain tissues together

  • Protecting joints

  • Facilitating the passage of light through the eye

A defective (FBN1) gene associated with Marfan syndrome affects the formation of a protein in connective tissue called fibrillin, which impacts the integrity of many organs and structures in the body. Organs and body systems that can be impacted include, but are not limited to, the following:

  • Heart and major blood vessels

  • Lungs

  • Skeletal system

  • Spinal cord

  • Eyes

  • Skin

According to the March of Dimes, more than 200,000 people in the U.S. are affected by Marfan syndrome. Marfan syndrome occurs in equal numbers in males and females, and also appears equally in all races and ethnic groups.

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, which is a sideways curvature of the spine, or kyphosis, which is a round curvature of the spine that can give the appearance of a hunchback

    • 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 health care provider for a diagnosis.

How is Marfan syndrome diagnosed?

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