FAH and Hepatic failure: Fah–/– mice were rescued by transplanting gene-corrected hepatocytes co-transduced ex vivo using lentiviral vectors containing Fah-aiming CRISPR-Cas9 and AAV vector containing a donor template.32 In a separate study, hepatocytes transduced utilizing a pair of AAVs to deliver Fah-CRISPR-Cas9 and donor template followed by culturing for up to 72 h were capable of engraftment in vivo and prevented liver failure.33 These studies demonstrate the feasibility of ex vivo gene editing in hepatocytes to treat IMDs of the liver.