Genetic Testing

Newborn screening is unique in being the only genetic testing that it is mandated by the state. The premise of newborn screening is that, for some disorders very early detection and initiation of treatment will prevent health problems, often mental retardation. All newborn infants are tested for a variety of genetic disorders. Each state determines for itself for what disorders to test their newborns. Disorders are chosen based on severity, incidence, ease and accuracy of testing, cost, and benefit of early diagnosis. All states test newborns for phenylketonuria (PKU), a metabolic disorder that is almost never evident at birth. Individuals with PKU are missing an enzyme called phenylalanine hydroxylase, which results in the buildup of phenylalanine. If left untreated, severe mental retardation develops. However, infants with PKU who are placed on a diet low in phenylalanine immediately after birth are expected to develop normally, making PKU an excellent candidate for newborn screening.