AGT and triple-A syndrome: We further verified by in vivo and in vitro experiments that the expression of LEF1 was significantly up‐regulated in the vascular wall of Ang II‐induced aortic aneurysms in mice and AAA patients, as well as in T cells infiltrated, suggesting that LEF1 has the potential to regulate AAA development through the modulation of T cells, and is highly likely to be a potential biomarker.