Genetics

Question 1

Question

Answer 1

Marfan syndrome (MFS) is one of the most common inherited connective tissue disorders. This condition is caused by a genetic defect in the glycoprotein fibrillin-1 and results in abnormalities in the skeleton (eg, long extremities, scoliosis, pectus excavatum), eyes (eg, ectopia lentis), and cardiovascular system (eg, aortic root disease).

The 2 most common cardiac abnormalities seen in MFS patients are mitral valve prolapse and cystic medial degeneration of the aorta. In more than 75% of MFS patients, cystic medial degeneration of the aorta results in aneurysmal dilation. If untreated, this can cause aortic dissection, the most common cause of death in MFS patients. The second most common cause of death is cardiac failure secondary to mitral valve prolapse and/or aortic regurgitation. For these reasons, MFS patients should be followed regularly by a cardiologist.

(Choices B, D, and E) With careful cardiovascular management, patients with MFS can have a normal life expectancy. MFS patients are not at increased risk for any of these other conditions.

(Choice C) Although homocystinuria is also associated with a marfanoid body habitus, distinguishing features of homocystinuria include intellectual disability and increased risk of thrombotic events (eg, myocardial infarction, stroke). However, this patient has no intellectual dysfunction.

Educational objective:
Cardiovascular lesions are the most life-threatening complications associated with Marfan syndrome. Early-onset cystic medial degeneration of the aorta predisposes to aortic dissection, the most common cause of death in these patients.

Question 2

Most common cardiac abnormalities in Marfans

2 listed

Answer 2

The 2 most common cardiac abnormalities seen in MFS patients are mitral valve prolapse and cystic medial degeneration of the aorta.

In more than 75% of MFS patients, cystic medial degeneration of the aorta results in aneurysmal dilation. If untreated, this can cause aortic dissection, the most common cause of death in MFS patients.

The second most common cause of death is cardiac failure secondary to mitral valve prolapse and/or aortic regurgitation. For these reasons, MFS patients should be followed regularly by a cardiologist.

Question 3

Marfan Syndrome Pathophysiology

Answer 3

Marfan syndrome (MFS) is one of the most common inherited connective tissue disorders.

This condition is caused by an autosomal dominant mutation in the glycoprotein fibrillin-1 and results in abnormalities in the skeleton (eg, long extremities, scoliosis, pectus excavatum), eyes (eg, ectopia lentis), and cardiovascular system (eg, aortic root disease).

Question 4

Difference between Marfans and Homocystinuria

Answer 4