| Feature | Marfan Syndrome | Homocystinuria |
|---|---|---|
| Inheritance | Autosomal Dominant | Autosomal Recessive |
| Defect | Fibrillin-1 | Cystathionine synthase |
| Lens Dislocation | Upward (“Marfan looks up”) | Downward (“Homocystinuria looks down”) |
| Intellect | Normal | Intellectual disability |
| CV Risk | Aortic dissection/aneurysm | Thromboembolism |
| Treatment | β-blockers, ARBs | Vitamin B6 (Pyridoxine) |