Behaviour and school achievement in patients with early and continuously treated phenylketonuria

Thirty patients with early and continuously treated phenylketonuria (PKU) b etween 8 and 20 years of age were compared with 30 controls, matched indivi dually for age, sex, and educational level of both parents, on behaviour ra ting scales for parents and teachers as well as a school achievement scale. PKU patients, as a group, demonstrated more problems in task-oriented beha viour and average academic performance than did matched controls. Interesti ngly, whereas male PKU patients were rated significantly lower on introvers ion by their teachers, female patients were rated significantly higher on i ntroversion and lower on extraversion than matched controls. This sex diffe rence was also reflected in the relationship between measures of dietary co ntrol and the behaviour clusters, suggesting that male and female patients respond differently to elevated Phe levels or the stress associated with PK U. The teacher rating on average academic performance of the PKU patients w as associated with recent level of dietary control, which suggests that it might be improved by more strict adherence to the diet. In addition, academ ic performance correlated negatively with the behaviour cluster negative ta sk orientation. Further studies are recommended to obtain a more complete e valuation of this relationship and to replicate the current findings on lar ger samples.