Background: Phenylketonuria (PKU) is the most common inborn error of metabolism in man. Brain phenylalanine kinetics can determine neurological treatment outcome in phenylketonuria. The aim of our study was to test a simplified magnetic resonance spectroscopy method for assessment of brain phenylalanine dynamics in PKU patients. Material/Methods: Brain phenylalanine concentration (measured by means of magnetic resonance spectroscopy) and blood phenylalanine concentrations changes occurring within 24 hours after oral phenylalanine loading were analyzed in 5 PKU patients. Results/Conclusions: The brain/blood phenylalanine ratio in 3 persons with normal intelligence was lower than in 2 with borderline intelligence or mild mental retardation. In our opinion the proposed method could be useful for assessment of brain phenylalanine dynamics in PKU patients
