Classic phenylketonuria with delayed initiation of dietary therapy: a case report
Abstract
Phenylketonuria is a rare inborn error of metabolism caused by a deficiency of the enzyme phenylalanine hydroxylase, which can lead to irreversible neurological damage. Although its incidence varies geographically, it remains one of the most significant conditions screened through neonatal testing.
Case presentation: A 7-month-old infant was diagnosed with classic phenylketonuria, confirmed at 8 weeks of age through elevated phenylalanine levels. Due to logistical delays, the infant continued on exclusive breastfeeding, which sustained hyperphenylalaninaemia. Following the introduction of a specialised metabolic formula, there was a marked improvement in plasma phenylalanine levels. Psychomotor development has remained appropriate, and the child continues under multidisciplinary follow-up.
Conclusion: This case highlights the importance of neonatal screening for the early detection of preventable metabolic disorders such as phenylketonuria. Timely dietary intervention prevented severe neurological complications, reinforcing the need to strengthen the Neonatal Metabolic Screening Programme and to ensure comprehensive follow-up in specialised centres.
Moreover, this report provides relevant regional clinical evidence and may serve as a reference for improving the management of similar cases in settings with limited prior experience.
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