Impact of a Phenylalanine-Restricted Diet on Gut Health in Children with PKU
Official title: Impact Of A Phenylalanine-Restricted Diet On The Microbiota Composition And Metabolome Of Children With PKU
Run by Birmingham Women's and Children's NHS Foundation Trust · NCT07728032 · Data updated 2026-11-12
This study looks at how a Phe-restricted diet, with or without sapropterin or sepiapterin, might affect gut health in kids with PKU.
Quick facts
| Study type | Observational |
|---|---|
| Ages | 3 Years to 17 Years |
| Sex | All |
| Enrollment | 148 (estimated) |
| Sponsor | Birmingham Women's and Children's NHS Foundation Trust Academic / other |
| Locations | 1 site (Birmingham) |
| Status | Recruiting |
| Started | October 1, 2025 |
| Main results expected | December 2026 |
| Study ends | December 2026 |
| Registry record updated | October 6, 2026 |
| Trial ID | NCT07728032 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Children and adolescents aged 3-17 with early-treated PKU receiving diet alone, sapropterin plus diet, or sepiapterin plus diet.
✕Probably not a fit
Individuals not eligible due to age, non-PKU metabolic disorders, or not meeting treatment criteria may not benefit from this observational assessment.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a single-centre, cross-sectional observational study at Birmingham Children's Hospital that explores how different PKU treatments and levels of dietary restriction relate to gut microbiota composition and function in children and adolescents aged 3-17. Participants are grouped by management: diet alone, sapropterin with diet, or sepiapterin with diet, with healthy household controls for comparison. Treatment decisions are made as part of routine care and not by the study, and eligible participants must have PKU with ongoing clinical management. Stool and clinical data are used to analyze associations between therapeutic approach, diet tolerance, and gut microbiota, aiming to understand potential links to gut health in PKU. The study includes at least one healthy control per PKU participant to account for household environmental factors.
Why it matters
Potential benefit: If successful, the study could clarify how PKU treatments and dietary practices influence gut health, potentially guiding more personalized dietary strategies.
How similar studies have gone: Previous work suggests diet and pharmacologic augmentation can alter gut microbiota in metabolic contexts, but this exact PKU-focused, cross-sectional gut microbiome study is relatively novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: Participants with PKU: * Aged 3-17 years. * Confirmed diagnosis of phenylketonuria following newborn screening. * Receiving ongoing clinical management for PKU. * For the diet-only cohort: managed with standard phenylalanine-restricted dietary treatment and not receiving sapropterin or sepiapterin. * For the sapropterin cohort: receiving sapropterin for at least three consecutive months and having achieved at least a 100% increase in natural protein tolerance compared with the pre-treatment prescription. * For the sepiapterin cohort: receiving sepiapterin for at least three consecutive months and having achieved at least a 100% increase in natural protein tolerance compared with the pre-treatment prescription. Healthy household controls: * Aged 3 years or older. * Living in the same household as a participating child or adolescent with PKU. * No known diagnosis of PKU or another inherited metabolic disorder. Exclusion Criteria: * Congenital malformations. * Chronic gastrointestinal disease. * Endocrine, liver, or kidney disease. * Other chronic medical conditions likely to affect gut microbiota composition. * Following a therapeutic diet for a medical condition other than PKU within the six months before stool sample collection.
Where it's running
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Birmingham Children's Hospital
Birmingham, United Kingdom Recruiting
Study contacts
- Principal investigator: Anita MacDonald, PhD — Birmingham Children's Hospital
- Study coordinator: Anita MacDonald, PhD
- Email: anita.macdonald@nhs.net
- Phone: +44 121 333 9999
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.