FAH and liver failure: These bipotent epithelial liver organoids could be differentiated into mature and functional hepatocytes in vitro and could rescue liver failure in the fumarylacetoacetate hydrolase (Fah−/−) mutant mouse, a model for tyrosinemia type I liver disease, after transplantation (Huch et al., 2013b; Broutier et al., 2016).