Classical galactosemia (deficiency of galactose-1-phosphate uridyltransferase, GALT) tyrosinemia type 1, hereditary fructose intolerance, urea cycle defects, and primary mitochondrial diseases constitute the most common causes of acute liver failure (ALF) among IMDs (Table 3) [26]. The gene discussed is GALT; the disease is inborn mitochondrial metabolism disorder.