Mitochondrial DNA content in hepatic failure. mtDNA depletion was not seen in patients with hepatic failure of non-mitochondrial etiology, although a small reduction in mtDNA was seen in patients with progressive familial intrahepatic cholestasis type 1 (PFIC1), Alagille syndrome (Alagille), Wilson disease (Wilson), and tyrosinemia type 1 (Tyrosinemia). Conversely, liver tissue from patients with two mutations in POLG, MPV17, DGUOK, and TK2 show marked mtDNA depletion, with mtDNA content less than 25% of the mean value for normal controls.