Whereas dysfunctional elastin has been associated with TAA, elastin insufficiency associates with inherited obstructive arterial diseases; heterozygous loss-of-function mutations in ELN, including deletion of the whole gene, cause supravalvular aortic stenosis and Williams Beuren Syndrome, but not aneurysm [85,279,280,281,282,283,284,285]. The gene discussed is ELN; the disease is aneurysm.