In this study, we derived iPS cells from the fibroblasts of FAH−/− mice, a mouse model of the acute and life-threatening disease tyrosinemia type 1 (fumarylacetoacetate hydrolase [FAH] deficiency) in humans [34], which we considered as a paradigm for an iPS cell–based gene therapy approach for orphan diseases, such as severe metabolic liver disorders. Here, FAH is linked to tyrosinemia type I.