In addition to endothelial cells, fibroblasts represent a critical cellular source and target of CNP12,35–37 and are a key cell type in the pathogenesis of AA.38,39 Using our established fibroblast-specific CNP-null mouse line (fbCNP−/−),12 we next determined the role of fibroblast-generated CNP in the development of TAA and AAA. This evidence concerns the gene CNP and triple-A syndrome.