Phenylketonuria is still a major cause of mental retardation in Tunisia despite the possibility of treatment

Abstract

Background and objective: Accumulation of phenylalanine following a deficiency of phenylalanine hydroxylase activity generates a brain damage with mental retardation: phenylketonuria (PKU). In the developing countries, where PKU systematic neonatal screening program is not established yet, the management of PKU handicap is not properly carried out. The aim of this study was to estimate the frequency of the PKU diagnosed following clinical features anomalies, to provide information about the untreated PKU patients profile in Tunisia not covered by neonatal screening. Also it is stressed that treated patients have a normal development.

Patients and methods: This is a retrospective study of 156 cases of PKU detected in Tunisia over 20 years following symptoms suggestive of inherited metabolic disease. Phenylalaninemia level was performed by fluorometric method. Among them 9 patients were treated.

Results: The PKU estimated frequency was 1/7631. The diagnosis mean age was 4 years. The phenylalaninemia mean was 1680 μmol/L; the classical PKU form accounted for 85.3% of cases and the dominant clinical symptoms were: mental retardation (88.2%), motor delays (87.7%), speech difficulties (83.2%) and pigmentation anomalies (61.7%). The treated patients responded to treatment and showed a normal development.

Conclusion: The establishment of neonatal screening should be a priority to avoid cases of mentally retardation.