Adverse Medical Outcomes of Early Newborn Screening Programs for Phenylketonuria

Phenylketonuria (PKU) causes mental retardation in infancy. The disease, if diagnosed at birth, is treated with a restrictive diet. Although universal screening for PKU, which began in the 1950s, is often described as a highly successful public health program, critics have argued that false-positive tests of children caused widespread harm. The researchers in this study sought to discover whether PKU screening programs did, in fact, cause adverse medical outcomes in children who ended up not having the disease. They collected data from medical archives, articles, and electronic databases. They also conducted oral interviews with people involved with the screening program in its early years.

Key Findings:

  • By 1966, 27 states had programs for PKU testing and 1 million infants had been screened.
  • The results showed no evidence of substantial numbers of children with false-positive results who had medically adverse outcomes.
  • No placebo-controlled clinical trials took place despite the fact there was little understanding of the effects of the treatment on different patients.

The results suggest this kind of program in the future should follow all identified children, including those with false-positive results, and document both the medical and psychosocial outcomes.