Metabolic Disorders

Bernardo Haddock Lobo Goulart, MD & Samanta Teixeira Basto, MD

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Marfan Syndrome

Introduction

The Marfan syndrome is an inherited disorder of connective tissue. It is characterized by skeletal abnormalities (pectus escavatum, pectus carinatum, scoliosis, high arched palate, tall stature, long arms and long fingers -arachnodactily); ocular abnormalities (characteristic upper dislocation of lens, myopia); ligamentar laxity and cardiovascular abnormalities (aortic dilatation, mitral valve prolapse and sometimes aortic dissection).

The disease is due to a mutation on the fibrillin gene. It can be inherited as a autossomal dominant trait. 60% to 70% of affected person have a positive family history.

Clinical manifestations

The patients may have diverse clinical manifestations. Thoracic abnormalities may progress as scoliosis during adolescence, or lead to spontaneous pneumothorax. The ocular ectopia of lens usually is in the upper direction and can lead to glaucoma and cataractsSee Eye Findings in Marfan's Syndrome. The diagnosis usually is made based on a tall individual with long fingers resembling a spider (arachnodactily), scoliosis or kyphosis, long arms, lens dislocation and mitral valve prolapse that can evolute to mitral regurgitation or aortic regurgitation due to aortic aneurism. Sometimes a ligamentous laxity similar to Ehler Danlos syndrome is observed.

The life threatening manifestation is aortic dissection that is related to the size of aortic dilatation. Aortic diameter increases with age, not exceeding the normal range until the third decade. Cardiac abnormalities are the major source of morbidity and mortality.

Diagnosis

Diagnosis can be made requiring at least two criteria in the 4 major areas (family history, cardiac, musculoskeletal or ocular anomalies).

Differential diagnosis

The Marfan syndrome must be distinguished from habitus marfanoid that occurs in other conditions that presents with similar characteristics of Marfan syndrome: 1) Congenital contractural arachnodactily: An inherited disorder that presents with joint contracture and arachnodactily but does not include lens or aortic abnormalities. 2) Homocystinuria: An metabolic inherited disease that causes ectopia lentis and some skeletal anomalies. 3) Familial ectopia lentis not associated with other manifestations of Marfan syndrome. 4) Other conditions as mitral valve prolapse syndrome, klineffelter syndrome, multiple endocrine neoplasia IIB.

Treatment

Treatment is directed to prevent aortic dissection, the most fearful complication of Marfan syndrome. Recent studies suggest use of beta blockers to delay aortic dilatation. Blood pressure should be controlled, and aortic surgery replacement is usually recommended when aortic diameter reaches around 50 to 60 mm. Regular care should include frequent echocardiography and regular ophthalmologic evaluation.

Bibliography

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