Phenylketonuria is an autosomal recessive genetic disorder and is the most common congenital amino acid metabolism disorder. The main clinical features include intellectual disability, pale skin and hair pigmentation, and a mouse-like urine smell. This condition is named after the high levels of phenylketonic acid metabolites excreted in the urine of affected patients. Phenylketonuria is an autosomal recessive genetic disease, and its primary pathological mechanism is due to the lack of phenylalanine hydroxylase, which fails to convert phenylalanine into tyrosine, leading to increased concentrations of phenylalanine in the blood, cerebrospinal fluid, and various tissues. Because the main metabolic pathway is blocked, secondary metabolic pathways are enhanced, leading to the deamination of phenylalanine and the production of large amounts of phenylketonic acid. Through oxidation, this produces byproducts such as phenylacetic acid, phenyllactic acid, and para-hydroxyphenylketonic acid, thereby resulting in a series of clinical symptoms.