First-year metabolic control guidelines and their impact on future metabolic control and neurocognitive functioning in children with PKU

There is a consensus on the importance of early and life-long treatment for PKU patients. Still, differences existon target blood phenylalanine (Phe) concentrations for children with PKU in different countries and treatmentcenters. For thefirst time, long-term metabolic control and child development and cognitive functioning iscompared between children with mean phenylalanine concentrations under 240μmol/L (group A), between 240and 360μmol/L (group B) or over 360μmol/L (group C) during theirfirst year of life. METHODS: 70 patientsdiagnosed with PKU through neonatal screening with Phe > 900μmol/L, were divided into 3 groups: A, B andC, according to mean Phe concentrations and standard deviation (SD). Metabolic control during childhood,psychomotor development and IQ were compared. RESULTS: In group A, Phe was maintained within the re-commended range until 6 years of age, in Group B, until 3 years of age, and in group C, Phe was always over therecommended range. No significant differences were found between the three groups in mental developmentindex (MDI) and motor development index (PDI) scores at 12, 24, and 30 months of age, but group C had thelowest scores on MDI at all age periods. At preschool and school age, IQ was higher in group A compared togroup C. CONCLUSION: Results show that mean blood Phe concentrations between 120 and 240μmol/L duringfirst year of life have a positive impact in metabolic control and cognitive functioning during childhood