TGFBR2 and triple-A syndrome: To gain in-depth insight into the functional importance of CCN2 for TGF-β pathway or vice versa in AAA, it would be interesting to know whether CCN2 expression/function is altered in SMC–TGF-βR2–KO mice; additional in vivo studies to determine whether CCN2 sufficiency or deficiency affects the AAA phenotype in animals deficient in SMC–TGF-βR2 are required.