Adult cognitive outcomes in phenylketonuria: explaining causes of variability beyond average Phe levels.
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ABSTRACT: OBJECTIVE:The objective was to deepen the understanding of the causes of individual variability in phenylketonuria (PKU) by investigating which metabolic variables are most important for predicting cognitive outcomes (Phe average vs Phe variation) and by assessing the risk of cognitive impairment associated with adopting a more relaxed approach to the diet than is currently recommended. METHOD:We analysed associations between metabolic and cognitive measures in a mixed sample of English and Italian early-treated adults with PKU (N =?56). Metabolic measures were collected through childhood, adolescence and adulthood; cognitive measures were collected in adulthood. Metabolic measures included average Phe levels (average of median values for each year in a given period) and average Phe variations (average yearly standard deviations). Cognition was measured with IQ and a battery of cognitive tasks. RESULTS:Phe variation was as important, if not more important, than Phe average in predicting adult outcomes and contributed independently. Phe variation was particularly detrimental in childhood. Together, childhood Phe variation and adult Phe average predicted around 40% of the variation in cognitive scores. Poor cognitive scores (>?1 SD from controls) occurred almost exclusively in individuals with poor metabolic control and the risk of poor scores was about 30% higher in individuals with Phe values exceeding recommended thresholds. CONCLUSIONS:Our results provide support for current European guidelines (average Phe value?=?
SUBMITTER: Romani C
PROVIDER: S-EPMC6883518 | biostudies-literature | 2019 Nov
REPOSITORIES: biostudies-literature
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