[Pathogenetic mechanisms in phenylketonuria: disorders affecting the metabolism of neurotransmitters and the antioxidant system]. / Mecanismos de patogenia en la fenilcetonuria: alteraciones del metabolismo de los neurotransmisores y del sistema antioxidante.

AIM: To review the clinical and biochemical changes in neurotransmission and antioxidant system in phenylketonuric patients under dietary treatment. DEVELOPMENT: Phenylketonuria (PKU) is an inborn error of metabolism caused by decreased activity of the enzyme L-phenylalanine-4-mono-oxigenase that synthesizes tyrosine from phenylalanine. According to analytical data from PKU patients and to experimental studies in animal models, high phenylalanine values in plasma and tissues seem to be related with defective biosynthesis of neurotransmitter (mainly serotonin and dopamine) and impairment of antioxidant system. Despite dietary treatment, PKU patients usually present moderate hyperphenylalaninemia over the evolution of the disease that might cause clinical and biochemical abnormalities. CONCLUSIONS: Increased plasma phenylalanine concentrations and dietary treatment might be related with neurotransmitter and antioxidant system abnormalities in human phenylketonuria. These biochemical alterations might be involved in the physiopathology of PKU.