The dietary management consists of a diet low in phenylalanine (i.e. low in native protein) with addition of amino acids supplements free from phenylalanine.
Phenylketonuria is an inherited rare disorder in metabolism of the amino acid phenylalanine. Individuals with PKU have a defect of the enzyme phenylalanine hydroxylase, which is responsible for the degradation of the amino acid phenylalanine. The consequence is an accumulation of phenylalanine and its metabolites in the body, which is toxic to the central nervous system. If not treated, this condition results in brain damages and mental retardation.