SynthesisOrphanet journal of rare diseases2025
Intelligence quotient scores among early-treated phenylketonuria patients: results from a systematic literature review.
Synthesis in Orphanet journal of rare diseases, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
4 citing papers in PubMed.
- Effects of a Prolonged-Release Protein Substitute on 24-h Phenylalanine and Tyrosine Profiles in Phenylketonuria: A Randomized Crossover Study.Nutrients · 2026Trial
- Psychometric validation of the NIH Toolbox for use with individuals with phenylketonuria: Evidence from the PHEFREE consortium longitudinal study.Journal of the International Neuropsychological Society : JINS · 2026Article
- Blood Phenylalanine Control in Paediatric and Adult Centres in the UK: Data from 2012-2018.Nutrients · 2026Article
- Development of a face-validated conceptual model structure for economic evaluation in phenylketonuria, through expert elicitation.Orphanet journal of rare diseases · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
12 authors.
Funding
Abstract
backgroundPhenylketonuria (PKU) is a rare condition that causes the accumulation of phenylalanine; without prompt diagnosis and treatment following birth, severe neurologic and cognitive impairments occur. While dietary management can help reduce Phe levels, adherence is challenging and deficits in cognitive function often remain. The importance of the exact features of dietary management, treatment, and control at different time points with respect to eventual IQ scores has not been established. The objective of the present study was to review and describe published data on the impact of PKU on cognition as measured by IQ among PKU patients receiving early dietary management.
methodsA systematic literature review was conducted following PRISMA guidelines to examine IQ among patients with PKU. Instruments used to assess IQ included the Wechsler Intelligence Scale, Culture Fair Intelligence Test and Stanford Binet Test. Results were reported overall and by subgroups.
resultsTwenty-five out of 28 identified studies could be included in the review. Lower IQ scores were generally observed among those with high phenylalanine levels, although variations in the study populations hinder the ability to make comparisons. Mean IQ scores among those with PKU were consistently lower compared to control groups. Even though all patients in this review received early treatment, those with poor dietary adherence and higher phenylalanine levels tended to show poorer cognitive ability.
conclusionsCognition is affected in PKU, despite early and continuous dietary management. Treatments are needed that reduce phenylalanine levels so that the burden of neurocognitive impairment in PKU can be alleviated.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.