EIF2AK3 and triple-A syndrome: In the present study, we provide experimental evidence that aberrant activation of the PERK/ATF4 stress response pathway directs VSMC-dysfunction and aortic aneurysm formation in 2 well-established murine AAA models (elastase-induced AAAs and angiotensin II–induced [AngII-induced] AAAs) and human aortic tissue samples.