Mental And Motor Development As Well As Temperament And Behavior In Children With Phenylketonuria

IntroductionPhenylketonuria (PKU) is an inborn error of the phenylalanine metabolism inherited as an autosomal recessive disease, affecting the enzyme phenylalaninehydroxylase (PAH), which converts phenylalanine to tyrosine. Without treatment, PKU patients will be severely mental retarded. The children with early treated PKU are almost normal in intelligence, but compared to healthy children, they may still have a high risk of motor development problems or cognitive dysfunction, as well as behavioral and emotional problems. Both the brain damage caused by the high phenylalanine concentration and the special social environment may be responsible for these problems. However, all the studies abroad about the children with early treated PKU mostly focus on school age children or adolescents, few attentions were paid to children younger than 3 years old, and much less reported in the Chinese population. In this study, mental and motor development temperament and behavior in 28 Chinese children with treated PKU aged from 3 to 36 months were investigated, in order to evaluate mental and motor development and psychosocial adjustment in the children with PKU in different geographies and with different culture backgrounds, and that will be helpful to improve the life quality for children with PKU.MethodsA total of 28 children, aged from 3 to 36 months, diagnosed with PKU at the Zhejiang Neonatal Screening Center, were enrolled. The control group, includes 73 healthy chronological age (CA)-matched and gender-matched children. The PKU group were evaluated by Bayley Scales of Infant Development (BSID) and Peabody Developmental Motor Scale (PDMS- II). For both PKU group and control group, the temperamental characters were assessed by the Toddler Temperament Questionnaire(TTQ), and the behavioral problems were measured by Achenbach's Child Behavior Checklist (CBCL), and the Socioeconomic Status (SES) of children's family as well as the family early education conditions were also measured.Results(1) The mental development index (MDI) and psychomotor development index (PDI) in the children with early treated PKU were normal.(2) No significant difference was found in temperament type between the PKU group and the control group. However, in temperamental dimensions, the children with PKU had a higher level in activity, more negative mood, less persistence and more distraction than control group.(3) The 2-3 year old PKU group presented a higher incidence of behavioral problems in depression and aggression.(4) Comparison of the mean blood phe concentration and the MDI showed linear regression, so as to the PDI. When the mean blood phe concentration increased 100μ mol/L, the MDI decreased by an average of 4.53, and PDI decreased by an average of 3.93. The mean blood phe concentration also has positive correlations with the measure of rhythmicity, persistence, aggression and depression in temperamental dimensions and behavior. There was no significant correlation between MDI, PDI and the concurrent blood phe concentration or the blood phe concentration before treatment.(5)The socioeconomic status(SES) of PKU children's family showed a positive effecton MDI, and negative correlations with the measure of rhythmicity, depression and destroy in temperamental dimensions and behavior.Conclusions(1) The mental and motor development showed no delay in early-treated PKU children.(2) PKU children presented higher level in activity, more negative mood, less persistence and more distraction in temperamental dimensions.(3) PKU children might have more behavioral problems in depression and aggression.(4) The mean blood phe level influence the mental and motor development as well as temperamental characters and behaviors in PKU children, when higher blood phe level leads to lower developmental index, less rhythmicity and persistence, more depression and aggression. However, neither the concurrent blood phe concentration nor the blood phe concentration before treatment has effect on the developmental index.(5) Higher SES of children's family showed a positive effect on MDI, temperamental characteristics and behavior in PKU children.