ADAR1 promotes the stability of matrix metallopeptidase 2 (MMP2) and matrix metallopeptidase 9 (MMP9) mRNA in SMC by interacting with the RNA-binding protein HuR, increases the expression and activity of MMP2 and MMP9, leads to elastin degradation and medial degeneration in the vessel wall, and finally forms AAA. The gene discussed is ADAR; the disease is triple-A syndrome.