Trial reportOrphanet journal of rare diseases2018
One-year follow-up of B vitamin and Iron status in patients with phenylketonuria provided tetrahydrobiopterin (BH4).
Trial report in Orphanet journal of rare diseases, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers, 2 of them syntheses that pooled it.
What it found
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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
12 citing papers in PubMed, 2 syntheses or guidelines pooled it, 15 citations in OpenAlex.
- Dietary Liberalization in Tetrahydrobiopterin-Treated PKU Patients: Does It Improve Outcomes?Nutrients · 2022Pooled it
- Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis.Nutrients · 2021Pooled it
- Article
- Ferroptosis inhibitors: mechanisms of action and therapeutic potential.Cellular and molecular life sciences : CMLS · 2025Review
- Risk of inadequate protein and micronutrient intakes in patients with PKU with an increased phe-tolerance: Impact of a micronutrient-dense protein substitute.Molecular genetics and metabolism reports · 2025Article
- A Cross-Sectional Study on Protein Substitutes for Paediatric Phenylketonuria Diet: Time to Pay Attention.Nutrients · 2025Article
- Ferroptosis at the nexus of metabolism and metabolic diseases.Theranostics · 2024Review
- Suitability and Allocation of Protein-Containing Foods According to Protein Tolerance in PKU: A 2022 UK National Consensus.Nutrients · 2022Article
- Complications of the Low Phenylalanine Diet for Patients with Phenylketonuria and the Benefits of Increased Natural Protein.Nutrients · 2022Review
- Cognitive analysis of metabolomics data for systems biology.Nature protocols · 2021Article
- Large neutral amino acid status in association with P:T ratio and diet in adult and pediatric patients with phenylketonuria.JIMD reports · 2019Article
- Biomarkers of Micronutrients in Regular Follow-Up for Tyrosinemia Type 1 and Phenylketonuria Patients.Nutrients · 2019Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
Abstract
backgroundPeople with Phenylketonuria (PKU) who respond to tetrahydrobiopterin (BH4) often decrease dependence on medical food (MF) following increased phenylalanine (phe) tolerance. Responders to BH4 may experience a reduction in certain nutrients if not compensated through intact foods or supplements. This study investigated B6, B12, folate, and iron status based on blood levels and dietary intake in patients with PKU responsive to BH4 over 1 year.
methodsFifty-eight patients with PKU, ages 4-50 years were recruited and initiated on BH4 therapy. Patients were monitored for BH4 response, and nutritional status was recorded at regular intervals over 12 months. The analysis included 33 patients with known BH4 response status and complete nutritional data. Nutrient intake was determined by National Data System for Research (NDSR) analysis of self reported 3 day diet records and compared to Dietary Reference Intakes (DRIs). Blood biomarkers were analyzed by Quest Diagnostics and compared to laboratory reference ranges. Patient laboratory values were compared to controls from the National Health and Examination Survey (NHANES). Differences in nutrient intakes across time points were examined, stratified by age, using nonparametric methods. Statistical analyses were completed with SAS 9.4, with significance set at α = 0.05.
resultsMedical food intake declined among pediatric (p < 0.01) and adult (p = 0.06) BH4 responders over 1 year. Among those < 18 years of age, mean percent of calories obtained from MF declined from 21.3 to 4.7%. In adults, percent calories from MF dropped from 19.5 to 4.0%. Though maintaining laboratory and dietary values within reference ranges, responders < 18 years experienced a significant decline in serum B12 (p = 0.01), dietary folate (p = 0.006), and dietary iron (p = 0.004) over the study.
conclusionAlthough mean dietary and laboratory values for B12, B6, folate, and iron in BH4 responders and non-responders were adequate at baseline and 12-month follow-up, responders experienced a significant decline in serum B12 over 1 year, which may be explained by decreased intake of fortified MF. Both response groups had lower serum B12 than NHANES controls at baseline and 12 months. Results indicate a need to monitor B12 concentrations and consider micronutrient supplementation, with special attention to pediatric patients with PKU.
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