Abstract: Tyrosinemia type 1 is an error of metabolism of tyrosine amino acid due to deficiency of the enzyme fumarylacetoacetate hydrolase (FAH). The incidence is 1 in 100,000 to 120,000 births. Symptoms include liver and kidney disturbances and mental retardation. Case report: the 2.5 months old girl admitted with chief complains of poor feeding, vomiting, fever and distended abdomen. She was the 5th child of the family and normal vaginal delivery, birth weight was 4.2 kg and normal development. Two sisters died with same symptoms at 1 and 1.5 months of age, respectively. Three days before admission, she presented with poor feeding, vomiting, fever, distended abdomen, blood and black stool. On admission, she presented with irritability, fever, edema, cold extremities, distended abdomen, and hepato-spleenomegaly. The routine investigations revealed coagulation disorder with prothrombin time (PT) of 22%, hypoalbuminemia (21.5 g/L), hyperlactatemia (7 mmol/L), increased AFP and increased infectious markers (CRP: 69 mg/dL). Plasma amino acids analysis and urinary GC/MS showed elevated plasma serin, lysine, tyrosine and urinary succinylacetone, 4-OH-phenyllactic, 4-OH-phenylpyruvic, phenyllactic and N-acetyltyrosine. She was managed with plasma infusion, vitamin K, glucose infusion, antibiotic. Her situation became better but PT and AFP was still low and too high, respectively, 3 weeks of treatment. This is the first Vietnamese patient diagnosed tyrosinemia type 1. The prognosis depends on treatment with nitisinone.
