Define Marfan Syndrome. Describe its clinical features, diagnosis and prognosis.

Definition

Marfan syndrome is an autosomal dominant connective-tissue disorder caused by mutations in the fibrillin-1 (FBN1) gene, affecting the skeleton, eyes and cardiovascular system.

Clinical Features

• Skeletal — tall stature, arachnodactyly (long fingers), arm span > height, joint hypermobility, pectus deformity, scoliosis, high-arched palate.
• Ocular — ectopia lentis (upward lens dislocation), myopia.
• Cardiovascular (life-threatening) — aortic root dilatation → dissection/rupture, and mitral valve prolapse.

Diagnosis & Management

• Clinical diagnosis using the Ghent criteria (major features + family history/genetics).
• Regular echocardiographic monitoring of the aorta; beta-blockers (± others) to slow aortic dilatation; prophylactic aortic surgery when indicated.
• Avoid strenuous/contact sports; ophthalmology follow-up; genetic counselling.

Differential Diagnosis

• Homocystinuria (also tall with lens dislocation — but DOWNward, plus thrombosis and intellectual disability).
• Other connective-tissue disorders (e.g. Loeys-Dietz, Ehlers-Danlos).

Systemic Surveillance

• Cardiology (echo of aortic root, mitral valve), ophthalmology (lens, retina), and orthopaedics (scoliosis).
• Multidisciplinary review through growth; genetic counselling (50% risk, autosomal dominant).

Emergency Awareness

An acute severe chest/back pain in a person with Marfan may signal aortic dissection — a surgical emergency; families should know the warning symptoms and the importance of adhering to surveillance and activity advice.

Prognosis

With aortic surveillance, beta-blockade, activity modification and timely surgery, life expectancy approaches normal; the outcome hinges on protecting the aorta.

Aortic dissection is the main cause of death — monitor the root.

A Note on WHY the Aorta Is What Kills

• The dominant fact in Marfan syndrome is understanding why these patients die — and it is not from their striking skeletal abnormalities but from the aorta.
• The mutation is in fibrillin-1 (FBN1) — the glycoprotein that forms the microfibrils on which elastic fibres are built.
• The tissues that suffer are therefore those richest in elastic tissue — and the most elastic structure in the body, subjected to the highest and most relentless mechanical stress, is the aortic root, which absorbs the full force of every cardiac ejection.
• Deprived of normal elastic support, the root progressively dilates — producing aortic regurgitation and, catastrophically, aortic dissection and rupture, which is the leading cause of death and may strike suddenly in a young, apparently well person.
• Understanding this dictates the entire management, which is directed at the aorta: lifelong regular echocardiographic surveillance of the aortic root; beta-blockers and/or an ARB (losartan, which blocks TGF-beta signalling) to reduce shear stress and slow the dilatation; prophylactic surgical root replacement once the diameter exceeds about 5 cm; avoidance of contact sports and isometric exercise; and specialist management of pregnancy, which is high-risk.