Esta página se tradujo automáticamente y no se garantiza la precisión de la traducción. por favor refiérase a versión inglesa para un texto fuente.

Impact Of A Phe-Restricted Diet On Gut Health In Children With PKU

21 de julio de 2026 actualizado por: Birmingham Women's and Children's NHS Foundation Trust

Impact Of A Phenylalanine-Restricted Diet On The Microbiota Composition And Metabolome Of Children With PKU

Phenylketonuria (PKU) is an inherited disorder of phenylalanine (Phe) metabolism. The mainstay of treatment is a Phe-restricted diet, which aims to maintain blood Phe concentrations within the recommended range and prevent neurological complications. Some individuals with PKU respond to pharmacological treatments, including sapropterin, a synthetic form of tetrahydrobiopterin (BH4), or sepiapterin. These treatments may increase Phe tolerance and allow a less restrictive diet.

Diet is an important determinant of gut microbiota composition and function. However, the effects of the Phe-restricted diet and pharmacologically enabled dietary relaxation on the gut microbiota in PKU remain poorly understood.

This observational study includes children and adolescents with PKU aged 3-17 years attending Birmingham Children's Hospital. Participants include those managed exclusively with a Phe-restricted diet, those receiving sapropterin, and those receiving sepiapterin. One healthy household control is recruited for each participant with PKU.

Faecal samples are collected for shotgun metagenomic sequencing and metabolite profiling. Dietary intake, gastrointestinal symptoms, stool characteristics, clinical information, and PKU treatment are also assessed.

The study investigates whether gut microbiota composition, microbial functional potential, and faecal metabolite profiles differ between participants managed with a Phe-restricted diet, those receiving pharmacological treatment, and healthy household controls. The findings may improve understanding of the relationships between PKU treatment, dietary restriction, gastrointestinal health, and the gut microbiome and may inform future nutritional strategies for individuals with PKU.

Descripción general del estudio

Estado

Reclutamiento

Condiciones

Intervención / Tratamiento

Descripción detallada

This is a single-centre, cross-sectional observational study conducted at Birmingham Children's Hospital. The study investigates the association between phenylketonuria (PKU) treatment, degree of dietary restriction, gastrointestinal health, and the composition and functional potential of the gut microbiota.

Children and adolescents aged 3-17 years with early-treated PKU are recruited into one of three cohorts according to their existing clinical management: treatment with a phenylalanine-restricted diet alone (anticipated n=30), treatment with sapropterin alongside an individualised phenylalanine-restricted diet (anticipated n=30), or treatment with sepiapterin alongside an individualised phenylalanine-restricted diet (anticipated n=14). Participants receiving sapropterin or sepiapterin have been receiving treatment for at least three months and have achieved at least a 100% increase in natural protein tolerance compared with their pre-treatment prescription. Treatment allocation, medication dosage, and dietary management are determined as part of routine clinical care and are not assigned or modified by the study.

One healthy household control is recruited for each participant with PKU. Household controls are aged 3 years or older and do not have PKU or another inherited metabolic disorder. Recruiting controls from the same household aims to reduce the influence of shared environmental factors, including living conditions and food availability, when comparing gut microbiota profiles. The anticipated total enrolment is 148 participants, comprising 74 participants with PKU and 74 household controls.

Each participant provides a single faecal sample. Samples are stored at -80°C and analysed using shotgun metagenomic sequencing to characterise microbial taxonomic composition, within-sample diversity, between-sample community differences, and microbial functional potential. Taxonomic profiles are assessed at multiple levels, including phylum, genus, and species. Functional annotation is used to characterise microbial genes, enzymes, and metabolic pathways.

Dietary intake is assessed using a 24-hour dietary recall, including natural protein intake, protein substitute intake, dietary fibre intake, and consumption of special low-protein foods. Gastrointestinal symptoms are assessed using the age-appropriate self-report or parent-proxy version of the PedsQL Gastrointestinal Symptoms Module, and stool form is assessed using the Bristol Stool Form Scale. Relevant demographic and clinical information, including age, sex, anthropometric measurements, PKU treatment, and metabolic control, is also collected.

The findings from this study may support the development of nutritional strategies and protein substitutes that more effectively promote gastrointestinal and metabolic health in individuals with PKU.

Tipo de estudio

De observación

Inscripción (Estimado)

148

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Estudio Contacto

Copia de seguridad de contactos de estudio

Ubicaciones de estudio

  • Reino Unido
    • Birmingham
      • Birmingham, Birmingham, Reino Unido, B4 6NH
        • Reclutamiento
        • Birmingham Children's Hospital
        • Contacto:

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

  • Niño

Acepta Voluntarios Saludables

Sí

Método de muestreo

Muestra no probabilística

Población de estudio

Children and adolescents aged 3-17 years with early-treated phenylketonuria receiving clinical care at Birmingham Children's Hospital are recruited into one of three cohorts according to their current treatment: a phenylalanine-restricted diet alone, sapropterin, or sepiapterin.

One healthy household control aged 3 years or older, without phenylketonuria or another inherited metabolic disorder, is recruited for each participant with phenylketonuria. All participants are enrolled according to predefined eligibility criteria.

Descripción

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.

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

Cohortes e Intervenciones

Grupo / Cohorte
Intervención / Tratamiento
PKU - Diet Only
Children and adolescents aged 3-17 years with early-treated phenylketonuria who are managed exclusively with a phenylalanine-restricted diet and are not receiving sapropterin or sepiapterin. Participants provide a faecal sample and undergo dietary, clinical, gastrointestinal symptom, and stool assessments.
Otro: Phenylalanine-restricted diet alone
Participants are managed with a phenylalanine-restricted diet and prescribed protein substitutes as part of their usual clinical care. They are not receiving sapropterin or sepiapterin. Dietary treatment is not assigned or modified by this observational study.
PKU - Sapropterin
Children and adolescents aged 3-17 years with early-treated phenylketonuria who have been receiving sapropterin for at least 3 months and have achieved at least a 100% increase in natural protein tolerance compared with before treatment. Sapropterin treatment is not assigned as part of this observational study. Participants provide a faecal sample and undergo dietary, clinical, gastrointestinal symptom, and stool assessments.
Droga: Sapropterin Dihydrochloride
Participants receive sapropterin as part of their usual clinical care, alongside an individualised phenylalanine-restricted diet. Sapropterin treatment and dosage are prescribed independently of this observational study and are not assigned or modified by the investigators.
Otros nombres:
  • Kuván
PKU - Sepiapterin
Children and adolescents aged 3-17 years with early-treated phenylketonuria who have been receiving sepiapterin for at least 3 months and have achieved at least a 100% increase in natural protein tolerance compared with before treatment. Sepiapterin treatment is not assigned as part of this observational study. Participants provide a faecal sample and undergo dietary, clinical, gastrointestinal symptom, and stool assessments.
Droga: Sepiapterin
Participants receive sepiapterin as part of their existing clinical management, alongside an individualised phenylalanine-restricted diet. Sepiapterin treatment and dosage are determined independently of this observational study and are not assigned or modified by the investigators.
Otros nombres:
  • Sefiencia
Healthy Household Controls
Healthy household members without phenylketonuria who are recruited at a ratio of one control for each participant with phenylketonuria. Controls provide a faecal sample and complete the relevant dietary, gastrointestinal symptom, and stool assessments.

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Faecal gut microbiota taxonomic composition assessed by shotgun metagenomic sequencing
Periodo de tiempo: At enrolment (single faecal sample collection)
Taxonomic profiles, expressed as the relative abundance of microbial taxa at phylum, genus, and species levels, are derived from shotgun metagenomic sequencing of one faecal sample per participant. Profiles are compared among participants with PKU managed by a phenylalanine-restricted diet alone, sapropterin, or sepiapterin and healthy household controls.
At enrolment (single faecal sample collection)

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Faecal gut microbiota alpha diversity assessed by shotgun metagenomic sequencing
Periodo de tiempo: At enrolment, based on a single faecal sample
Within-sample microbial diversity is assessed from shotgun metagenomic sequencing data using alpha-diversity indices, including Shannon, Simpson, Chao1, ACE, and observed species. Alpha-diversity measures are compared across the study cohorts.
At enrolment, based on a single faecal sample
Faecal gut microbiota beta diversity assessed by shotgun metagenomic sequencing
Periodo de tiempo: At enrolment, based on a single faecal sample
Differences in overall microbial community composition between participants are assessed using beta-diversity measures derived from shotgun metagenomic sequencing data, including Bray-Curtis dissimilarity. Microbial community profiles are compared across the study cohorts.
At enrolment, based on a single faecal sample
Microbial functional potential assessed by shotgun metagenomic sequencing
Periodo de tiempo: At enrolment, based on a single faecal sample
Microbial genes and functional pathways are characterised from shotgun metagenomic sequencing data using functional annotation databases. The relative abundance of microbial genes, enzymes, and metabolic pathways is compared across the study cohorts.
At enrolment, based on a single faecal sample
Gastrointestinal symptom burden assessed using the PedsQL Gastrointestinal Symptoms Module
Periodo de tiempo: At enrolment, based on a single faecal sample
Gastrointestinal symptoms are assessed using the age-appropriate self-report or parent-proxy version of the PedsQL Gastrointestinal Symptoms Module. Total and individual symptom-domain scores are calculated, with lower scores indicating a greater gastrointestinal symptom burden, and compared across the study cohorts.
At enrolment, based on a single faecal sample
Stool form assessed using the Bristol Stool Form Scale
Periodo de tiempo: At enrolment, based on a single faecal sample
Usual stool form is classified using the Bristol Stool Form Scale, ranging from type 1, representing separate hard lumps, to type 7, representing entirely liquid stool. Stool-form distributions are compared across the study cohorts.
At enrolment, based on a single faecal sample
Dietary intake assessed using a 24-hour dietary recall
Periodo de tiempo: At enrolment, based on a single faecal sample
Dietary intake is assessed using a 24-hour dietary recall. Nutrient and food-group measures, including natural protein intake, protein substitute intake, dietary fibre intake, and consumption of special low-protein foods, are estimated and compared across the study cohorts.
At enrolment, based on a single faecal sample

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Birmingham Women's and Children's NHS Foundation Trust

Colaboradores

Universidade Nova de Lisboa

Investigadores

  • Investigador principal: Anita MacDonald, PhD, Birmingham Children's Hospital

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Actual)

1 de octubre de 2025

Finalización primaria (Estimado)

1 de diciembre de 2026

Finalización del estudio (Estimado)

1 de diciembre de 2026

Fechas de registro del estudio

Enviado por primera vez

21 de julio de 2026

Primero enviado que cumplió con los criterios de control de calidad

21 de julio de 2026

Publicado por primera vez (Actual)

27 de julio de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

27 de julio de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

21 de julio de 2026

Última verificación

1 de julio de 2026

Más información

Términos relacionados con este estudio

Términos MeSH relevantes adicionales

Otros números de identificación del estudio

  • IRAS project ID: 353831

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

NO

Descripción del plan IPD

There is no current plan to share individual participant data because the study involves a small population with a rare condition, which may increase the risk of participant identification. Any future data sharing would be subject to participant consent, ethical and institutional approvals, and an appropriate data-sharing agreement. Aggregated study results will be disseminated through scientific publications and presentations.

Información sobre medicamentos y dispositivos, documentos del estudio

Estudia un producto farmacéutico regulado por la FDA de EE. UU.

No

Estudia un producto de dispositivo regulado por la FDA de EE. UU.

No

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

Suscribir