Phenylketonuria (PKU) is a genetic disorder that affects how the body processes an amino acid called phenylalanine. People with PKU lack an enzyme called phenylalanine hydroxylase, which is necessary to convert phenylalanine into another amino acid, tyrosine. When phenylalanine builds up in the body, it can lead to serious health issues, including intellectual disabilities and neurological problems. PKU is typically diagnosed through newborn screening tests. If detected early, a strict diet low in phenylalanine can help manage the condition and prevent complications. This diet often includes special medical foods and avoids high-protein items like meat, dairy, and certain grains.