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Effects of dietary management of phenylketonuria on long-term cognitive outcome

Shelley Channon1, Galya Goodman, Sally Zlotowitz

  • 1University College London, National Hospital for Neurology and Neurosurgery, London, UK.

Archives of Disease in Childhood
|October 28, 2006
PubMed

Insights

Phenylketonuria (PKU) patients who stopped their diet in adolescence showed subtle cognitive deficits compared to those on continuous diet. Early treatment benefits for PKU may be enhanced by maintaining the diet longer.

Area of Science:

  • Neuroscience
  • Metabolic Disorders
  • Cognitive Psychology

Background:

  • Phenylketonuria (PKU) is linked to reduced dopamine and myelination issues in the brain, potentially causing cognitive impairments.
  • Early treatment of PKU suggests benefits for cognitive outcomes when the diet is maintained through adolescence.

Purpose of the Study:

  • To evaluate cognitive deficits in adults with PKU who stopped their dietary treatment in adolescence.
  • To compare cognitive function in early-treated PKU adults who discontinued diet versus those on continuous diet and healthy controls.

Main Methods:

  • Compared 25 adults with PKU off-diet in adolescence to 25 adults with PKU on continuous diet and 45 healthy controls (all aged 18-38).
  • Utilized n-back working memory and flanker inhibitory tasks to assess cognitive performance.

Main Results:

  • Significant group differences were found in working memory accuracy and speed (n-back task) and inhibitory control speed (flanker task).
  • The off-diet PKU group performed worse than the on-diet group on working memory accuracy and inhibitory control speed.
  • The off-diet PKU group also showed slower performance on working memory speed compared to healthy controls.

Conclusions:

  • Discontinuing the PKU diet in adolescence appears to have disadvantages for cognitive function compared to continuous dietary management.
  • Despite observed differences, the cognitive deficits in adults with PKU who stopped their diet in adolescence are relatively subtle.
Abstract

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