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Neuropsychological function in mild hyperphenylalaninemia

M L Smith1, J Saltzman, P Klim

  • 1University of Toronto at Mississauga. smithml@psych.utoronto.ca

American Journal of Mental Retardation : AJMR
|February 7, 2001
PubMed

Insights

Mild hyperphenylalaninemia (MHP) does not appear to cause cognitive deficits. Individuals with MHP showed no significant differences in executive function or other cognitive measures compared to controls.

Area of Science:

  • Neuroscience
  • Metabolic Disorders
  • Genetics

Background:

  • Phenylketonuria (PKU) is associated with cognitive deficits due to frontal-lobe dysfunction.
  • Mild hyperphenylalaninemia (MHP) involves milder elevations in phenylalanine levels than PKU.

Purpose of the Study:

  • To investigate if cognitive deficits seen in PKU are also present in individuals with MHP.
  • To determine if mild phenylalanine elevations impact executive function and cognitive control.

Main Methods:

  • Administered executive function tests and control tasks to individuals with MHP and a control group.
  • Matched groups for age, gender, and IQ.
  • Included academic skills tests and behavior-rating questionnaires for the MHP group.

Main Results:

  • No significant group differences were observed in executive function or control tasks.
  • Academic skills and behavioral ratings in the MHP group did not show impairments.

Conclusions:

  • Mild hyperphenylalaninemia is not sufficient to cause the cognitive impairments characteristic of PKU.
  • Elevated phenylalanine levels in MHP do not appear to lead to behavioral or cognitive deficits.

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