Screening the Normal Population in Massachusetts for Phenylketonuria

Abstract

To ascertain the prevalence of phenylketonuria among the "normal" teen-age and adult population of Massachusetts, a total of 280,919 serum specimens submitted for routine syphilis testing were examined for elevated phenylalanine concentrations by a bacterial inhibition assay ("Guthrie test"). It was estimated that these represented about 250,000 separate persons. Only three adults with the biochemical findings of phenylketonuria were detected although, on the basis of findings from routine newborn screening, 17 cases might be anticipated in the general population. Each of the three adults was mentally subnormal. Mental normality is very rare among patients with phenylketonuria who have not received dietary therapy.