Despite evidence for similar levels of oxidative stress throughout the abdominal and thoracic aortic walls of d-alanine–fed DAAO-TGTie2 transgenic mice, only the abdominal aorta shows evidence of wall thinning (Figure 3, I and J) and elastin breaks (Figure 3, K and L), and only the abdominal aorta develops aneurysms leading to premature death (Figure 2). This evidence concerns the gene ELN and aneurysm.