Citrin deficiency typically presents as neonatal intrahepatic cholestasis and resolves in late infancy.Here we report a case of citrin deficiency that presented as acute liver failure in late infancy in an apparently healthy child. The full-term male infant weighed3400 g at birth, and exhibited normal development for eight months, at which time he contracted bronchial pneumonia. The infant developed jaundice and laboratory tests indicated elevated bilirubin and ammonia levels and an abnormal coagulation profile.Plasma amino acid analysis showed elevated levels of tyrosine, methionine, citrulline, and arginine. Citrin deficiency was suspected, and genomic DNA analysis revealed a mutation(IVS16ins3kb) in SLC25A13, which encodes a mitochondrial aspartate-glutamate carrier protein. The infant was immediately put on a lactosefree,medium-chain-triglyceride-enriched formula with ursodeoxycholic acid and lipid-soluble vitamins.However, cholestasis and abnormal laboratory indices persisted, and the infant died at the age of 11.5 mo,two days before a scheduled liver transplantation. This case demonstrates that citrin deficiency can present in late infancy as acute liver failure triggered by infection,and may require liver transplantation. Citrin dose typically presented as neonatal intrahepatic cholestasis and resolves in late infancy. Here we report a case of citrin deficiency that presented as acute liver failure in late infancy in an apparently healthy child. The full-term male infant weighed 3400 g at birth, and exhibited The infant developed jaundice and laboratory tests indicated elevated bilirubin and ammonia levels and an abnormal coagulation profile. Plasma amino acid analysis showed elevated levels of tyrosine, methionine, citrulline, and arginine. Citrin deficiency was suspected, and genomic DNA analysis revealed a mutation (IVS16ins3kb) in SLC25A13, which encodes a mitochondrial aspartate-glutamate carrier protein. The infant was immediately put on a lactose free, medium-chain-triglyceride-enriched formula with ursodeoxycholic acid and lipid -soluble vitamins. Despite, cholestasis and abnormal laboratory indices persisted, and the infant died at the age of 11.5 mo, two days before a scheduled liver transplantation. This case demonstrates that citrin deficiency can present in late infancy as acute liver failure triggered by infection, and may require liver transplantation.