MMP13 and congenital secretory chloride diarrhea 1: Consistent with these histological observations, qPCR analyses of liver gene expression showed marked up-regulation of several genes associated with liver fibrogenesis, including collagen Iα1 (ColIα1), the interstitial collagenase matrix metalloproteinase 13 (Mmp13) and its inhibitor Timp1, lysyl oxidase (Lox) and transforming growth factor β2 (Tgfβ2), a TGFβ isoform strongly involved in biliary damage-related CLD [68] (Figure 4a).