Tyrosinemia type I is caused by the accumulation of tyrosine in the body due to a defect in the enzyme johnsonyl acetoacetate hydrolase, the final enzyme in the tyrosine metabolism process, which causes damage to the body. Tyrosinemia type I can develop at any age, but most patients develop it in neonates and infants, and the clinical manifestations are varied, even among patients of the same family. Tyrosinemia type I can be diagnosed directly according to the age of onset of the disease, which is divided into acute and chronic types. Acute tyrosinemia type I: Patients with acute tyrosinemia type I most often develop within the first 6 months of life, with vomiting, diarrhea, weight gain, hepatomegaly, jaundice, ascites, bleeding, hypoglycemia and edema also common after birth. If left untreated, the disease can rapidly progress to liver failure and severe coagulation abnormalities, and patients mostly die of liver failure within 6 to 8 months after birth; survivors enter the chronic phase and eventually develop chronic liver insufficiency, cirrhosis or hepatocellular carcinoma. Chronic tyrosinemia type I: Patients with chronic tyrosinemia type I are relatively stable and have mild clinical manifestations, with symptoms appearing after 6 months of life. A few patients have hypoglycemic manifestations. Complications of cardiomyopathy and hepatocellular carcinoma as the first symptom have also been reported.