Newborn screening originated with an amino acid disorder, phenylketonuria (PKU), which can be easily treated by dietary modifications, but causes severe mental retardation if not identified and treated early. Robert Guthrie introduced the newborn screening test for PKU in the early 1960s.[4] With the knowledge that PKU could be detected before symptoms were evident, and treatment initiated, screening was quickly adopted around the world. Austria started screening for PKU in 1966[5] and England in 1968.[6]