Cognitive Functioning and Neuropsychiatric Outcomes in Phenylketonuria

Phenylketonuria (PKU) is a hereditary metabolic disorder in which insufficient activity of phenylalanine hydroxylase leads to elevated levels of phenylalanine in blood and brain. Early dietary treatment mitigates severe intellectual disability, yet even well controlled patients exhibit subtle impairments in executive functions, processing speed and sustained attention. Neuropsychiatric sequelae such as mood instability, anxiety and attentional disorders are reported across the lifespan. Neuroimaging studies reveal widespread white matter microstructure alterations, reduced volumes of subcortical grey matter and abnormal cerebral blood flow patterns. Emerging molecular models highlight gene expression changes underlying neuronal connectivity deficits. Advances in enzyme substitution and large neutral amino acid supplementation offer new therapeutic avenues beyond dietary restriction. Integrating metabolic control, neuroimaging and molecular profiling is enhancing our understanding of PKU’s impact on brain structure, cognitive function and mental health, informing refined guidelines for lifelong management and novel pharmacological interventions.

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Cognitive Functioning and Neuropsychiatric Outcomes in Phenylketonuria publication trend

The graph below shows the total number of articles in cognitive functioning and neuropsychiatric outcomes in phenylketonuria across all publications each year (not limited to Nature Index journals).

Technical terms

Phenylketonuria (PKU): An inherited metabolic disorder caused by deficient phenylalanine hydroxylase activity, leading to elevated phenylalanine and risk of neurotoxicity.

Phenylalanine: An essential amino acid whose accumulation in PKU disrupts neurotransmitter synthesis and myelin formation in the brain.

Executive functions: Higher-order cognitive processes including working memory, inhibitory control and cognitive flexibility, often affected in PKU.

Diffusion tensor imaging: An MRI technique that measures the directional diffusion of water molecules to assess white matter microstructure.

Fractional anisotropy: A diffusion tensor imaging metric indicating the degree of directional water diffusion and integrity of white matter fibres.

Transcriptome profiling: Comprehensive analysis of gene expression patterns in cells or tissues, revealing molecular responses to phenylalanine exposure.

References

1. Cognition after a 4-week high phenylalanine intake in adults with phenylketonuria – a randomized controlled trial. American Journal of Clinical Nutrition (2024).
2. Transcriptome Profiling of Phenylalanine-Treated Human Neuronal Model: Spotlight on Neurite Impairment and Synaptic Connectivity. International Journal of Molecular Sciences (2024).
3. Volumetric brain reductions in adult patients with phenylketonuria and their relationship with blood phenylalanine levels. Journal of Neurodevelopmental Disorders (2024).
4. Cerebral blood flow and white matter alterations in adults with phenylketonuria. NeuroImage Clinical (2023).
5. Compromised white matter is related to lower cognitive performance in adults with phenylketonuria. Brain Communications (2023).
6. Psychiatric and Cognitive Aspects of Phenylketonuria: The Limitations of Diet and Promise of New Treatments. Frontiers in Psychiatry (2019).
7. Effect of enzyme substitution therapy on brain magnetic resonance imaging and cognition in adults with phenylketonuria: A case series of three patients. European Journal of Neurology (2024).
8. Large Neutral Amino Acid Supplementation Exerts Its Effect through Three Synergistic Mechanisms: Proof of Principle in Phenylketonuria Mice. PLOS ONE (2015).
9. A systematic review of cognitive functioning in early treated adults with phenylketonuria. Orphanet Journal of Rare Diseases (2018).