Medical Genetics

Marfan syndrome

An autosomal-dominant FBN1-related connective-tissue disorder affecting the aorta, eyes and skeleton; tall stature and ectopia lentis are recognisable clues, but progressive aortic-root disease and dissection are the life-threatening priorities.

Definition

Marfan syndrome is an autosomal-dominant heritable connective-tissue disorder caused most often by a pathogenic FBN1 variant. It has variable cardiovascular, ocular, skeletal and other systemic manifestations and is diagnosed using the revised Ghent framework.

First principles

FBN1 variants weaken connective tissue

FBN1 encodes fibrillin-1, a structural component of extracellular microfibrils. Pathogenic variants disrupt tissue integrity and signalling, producing a variable multisystem phenotype involving the aortic root, eyes, skeleton, skin, lungs and dura.

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