Importantly, Stephanie and colleagues reported a mild and chronic inflammation in intestinal biopsies from a post-LT PFIC1 patient,16 while Henkel and colleagues recently reported on a post-LT PFIC1 patient who had developed colitis specifically in the distal colon.10 Hence, our observations indicate an essential function for ATP8B1 in the establishment of the intestinal barrier, and suggest strongly that a ‘second hit’ is required to expose a barrier defect as well as colitis when ATP8B1 levels are reduced/absent. Here, ATP8B1 is linked to colitis.