Phenylketonuria is a common amino acid metabolic disease, mainly due to the deficiency of phenylalanine hydroxylase, which prevents phenylalanine from being transformed into tyrosine, leading to the accumulation of phenylalanine and its keto acids. Due to the lack of tyrosine in the body, it affects the growth and development of the brain, resulting in intellectual developmental delays. Therefore, children with phenylketonuria often exhibit intellectual disabilities, as well as some psychiatric and neurological symptoms, such as increased muscle tone, restlessness, hyperactivity, abnormal behavior, and heightened excitability.