Besides diarrhoea, >90% of post-LT PFIC1 patients rapidly develop hepatic steatosis/steatohepatitis, both of which are reversible upon interruption of the enterohepatic circulation.9,17,26,29–31 We propose that increased bile salt entry into the intestine of post-LT PFIC1 patients serves a ‘second hit’ that damages the intestinal epithelium, causing epithelial barrier defects and consequent diarrhoea and inflammation, and triggers hepatic steatosis. The gene discussed is ATP8B1; the disease is fatty liver disease.