Phenylketonuria generally does not cause abnormalities in liver function. Phenylketonuria is a common amino acid metabolic disorder, mainly due to a deficiency of an enzyme in the phenylalanine metabolic pathway, preventing phenylalanine from being converted into tyrosine. This leads to the accumulation of phenylalanine and its keto acids, which are then excreted in large amounts in the urine. This disease is a relatively common genetic amino acid metabolic defect. Once diagnosed with phenylketonuria, the main treatment is a dietary therapy, which includes a low-phenylalanine diet. It is important during the upbringing of children to ensure that the child's living environment is quiet and comfortable. Therefore, in terms of prevention of the disease, it is important to avoid consanguineous marriage, conduct newborn screening, and focus on early detection and early treatment.