Epidemiology
Etiology
Marfan syndrome
- Mutation of fibrillin-1 gene (FBN1) on chromosome 15 → defective fibrillin (a glycoprotein that forms a supportive sheath around elastin) → defective connective tissue microfibrils → defective elastin
- Autosomal dominant inheritance pattern with variable penetrance
Mnemonic
MarFan syndrome is caused by a gene mutation in FBN1 on chromosome 15 (Fifteen), resulting in defective Fibrillin protein.
Ehlers-Danlos syndrome
- Mutations in genes (e.g., COL5A1, COL3A1) that control the synthesis and processing of different types of collagen → collagen defects (e.g., a defect in lysine-hydroxylysine cross-linking of tropocollagen leads to unstable collagen fibrils)
Pathophysiology
Clinical features
Tip
The classic presentation of MFS includes aortic aneurysm or dissection, long extremities, arachnodactyly, joint hypermobility, and subluxation of the lens of the eye.
Diagnostics
