Marfan syndrome

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Marfan's syndrome

Pectus excavatum

Marfan syndrome is an inheritable disorder of connective tissue, the tissue that strengthens the body's structures. Disorders of connective tissue affect the skeletal system, cardiovascular system, eyes, and skin.

Marfan syndrome is inherited as an autosomal dominant trait. However, up to 30% of cases have no family history and are so-called "sporadic" cases. In sporadic cases, Marfan syndrome is believed to result from a spontaneous new mutation.

Marfan syndrome is caused by mutations in the gene fibrillin-1. Fibrillin-1 plays an important role as the scaffolding for elastic tissue in the body. Disruption of such scaffolding (by mutations in fibrillin-1) results in changes in elastic tissues, particularly in the aorta, eye, and skin. Mutations in fibrillin-1 also cause overgrowth of the long bones of the body, resulting in the tall stature and long limbs seen in Marfan patients.

How this overgrowth happens is not well understood. Marfan syndrome causes skeletal defects typically seen in a tall, lanky person with long limbs and spider-like fingers (arachnodactyly), chest abnormalities (pectus excavatum or pectus carinatum), curvature of the spine, and a particular set of facial features, including a highly arched palate and crowded teeth.

Common eye problems are nearsightedness and dislocation of the lens of the eye.

The most significant of the defects in the syndrome are cardiovascular abnormalities, which may include enlargement (dilatation) of the base of the aorta (aortic root), with aortic regurgitation, and prolapse of the mitral valve. Affected people may develop a dissecting aortic aneurysm.

Review Date: 04/20/2005
Reviewed By: Neal Sondheimer, M.D., PhD., Division of Genetics and Metabolism, Children's Hospital of Philadelphia, Philadelphia, PA. Review provided by VeriMed Healthcare Network.