Phenylketonuria (PKU) is a genetic disorder characterized by an inability to metabolize the amino acid phenylalanine due to a deficiency in the enzyme phenylalanine hydroxylase (PAH). This enzyme normally converts phenylalanine to tyrosine, another amino acid. In individuals with PKU, the build-up of phenylalanine can lead to severe neurological damage and cognitive impairment if left untreated.
