REN and triple-A syndrome: The closest gene within the linkage signal on chromosome 7 is EGFR. Activation of EGFR is important in the regulation of vascular smooth muscle cells growth, proliferation, and response to injury [47], and has been previously demonstrated to mediate the renin-angiotensin II hypertrophic effect on vascular smooth muscle cells, oxidative stress and interleukin-6 induction, and the chemokine induction of pro-matrix metalloptroteinase2, all leading to AAA [48].