Phenylketonuria Phenylketonuria (PKU) is a disease of the nervous system caused by the lack of an enzyme which breaks down the amino acid phenylalanine. The defective version of the gene is recessive. Infants who have two defective

just as testing for phenylketonuria (PKU) has been since the 1960s. A person’s individual genome would become part of a data bank to which each of us, as well as our health care providers, would have future access. The advantage is