To clarify the role of Treg‐derived Tff1 in AAA and determine whether it affected SMC apoptosis, mice expressing a Tff1 conditional allele (Tff1flox/flox) were crossed with Foxp3‐cre mice to specifically ablate Tff1 expression in Tregs (Figure 6c), while the expression of Tff1 in the stomach was not affected in these mice (Figure 6d). Here, FOXP3 is linked to triple-A syndrome.