Although the exact mechanism is not fully defined, the current understanding of MVP and aortic aneurysm formation in MFS is that altered matrix sequestration of latent TGF-β increases bioavailability of TGF-β, and increased signaling drives disease pathogenesis rather than deficient structural integrity of tissue from abnormal fibrillin-1 microfibrils (10). The gene discussed is FBN1; the disease is aortic aneurysm.