Physical growth in phenylketonuria: I. A retrospective study.

A retrospective cross-sectional survey of phenylketonuria (PKU) was conducted in 1967. Questionnaires on 693 patients, clinically thought to have PKU, were reanalyzed to obtain information on growth in height and head circumference in patients with untreated and previously treated PKU. To provide a comparison to the growth findings of the Collaborative PKU Study, a definition of PKU was adopted to correspond to the one used in that study. Stature in 232 outpatients with untreated PKU was normal but, in 31 institutionalized individuals, the mean height was -1.4 standard deviations below the mean of a normal population. Head circumference in patients with untreated PKU was normal at birth, but showed an increasingly negative deviance with age and was -1.4 SD in untreated adults. Height measurements of 135 children with PKU in whom treatment was started before 121 days of age (age chosen to coincide with criteria for the Collaborative Study) had a significant reduction in height growth, -.8 SD. Head circumference measurements of 115 children treated for PKU were -.7 SD of normal. The depression in head circumference was less in treated subjects with PKU than in untreated ones of the same age. These findings are corroborated by a review of the literature, which contains no convincing report of normal growth during treatment of PKU.