PKU Protein Requirements

Not Applicable

Not yet recruiting

• Conditions: PKU

• Registration Number: NCT07194993
• Lead Sponsor: Emory University

Brief Summary

The objective of this research is to determine the protein requirements based on genotype and medical food consumption in a sample of adults with Phenylketonuria (PKU) using the indicator amino acid oxidation (IAAO) method.

Detailed Description

Current phenylketonuria (PKU) protein guidelines are based on outdated methods and do not account for differences in genetics or how much medical formula an individual consumes. This research aims to determine more accurate and personalized protein requirements in adults with PKU that have different genetic changes using a safe and direct method called the indicator amino acid oxidation technique. The study will address two specific aims: Aim 1 will determine the protein requirements of adults with PKU that have different genetic changes and Aim 2 will investigate how the ratio of medical formula to protein intake from natural foods affects protein needs.

Adults with PKU will be recruited for this study, and vulnerable populations will not be included.

This study includes surveys, anthropometric measurements, body composition analysis, indirect calorimetry, diet history, collection of blood, urine, and expired breath samples, administration of study day diets and an oral stable isotope protocol.

Recruitment will be at Emory Genetics Clinic. Informed consent will be obtained with an in-person signature or by an electronic IRB approved signature. Participants will attend one preliminary visit and 7 study days. Each study day will last 8 hours. Participants will be enrolled for approximately 4-6 months.

Participants will have the option to bank plasma and urine samples for future use.

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-19
• Study First Submitted QC: 2025-09-19
• Last Update Submitted: 2025-09-19
• Study First Posted: 2025-09-26
• Last Update Posted: 2025-09-26
• Study Start: 2025-11-01
• Primary Completion: 2027-08
• Study Completion: 2027-08-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 12

Inclusion Criteria

• will be males and females (50:50) 18 years and older who were diagnosed with PKU through newborn screening or diagnosis later in life, capable of providing consent, and have previously had mutation testing

Exclusion Criteria

• include concurrent illness, recent history of weight loss or acute illness during the past 6 months that could affect protein metabolism, pregnancy, lack of regular menstruation, implantable electronic devices or pacemakers, history of claustrophobia, and inability to provide consent. In addition, participants will be excluded if their genotype subgroup has already reached its predefined maximum enrollment (n=4)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Primary Outcome Measures

Name	Time	Method
Change in rate of oxidation of tracer in the expired breath	Baseline, post-intervention (3-8 hours post-baseline)	The rate of oxidation of tracer in the expired breath will be measured in each study day.

Secondary Outcome Measures

Name	Time	Method
Change in Phenylalanine concentrations before and after provision of the oral isotope protocol to provide an assessment of phenylalanine and tyrosine metabolism following study day	Baseline, post-intervention (8 hours post-baseline)	Phenylalanine concentration before and after provision of the oral isotope protocol to provide an assessment of phenylalanine metabolism following study day diets.
Change in Tyrosine concentrations before and after provision of the oral isotope	Baseline, post-intervention (8 hours post-baseline)	Tyrosine concentrations before and after provision of the oral isotope protocol to provide an assessment of tyrosine metabolism following study day diets.
Ratio of medical food protein to protein from foods protein to protein from foods	Throughout the study (Up to 6 months post-intervention)	Ratio of medical food protein to protein from foods as reflected on 3-day diet records throughout the study.
Number of participants with no adverse events related to study day diets and nonradioactive isotope tracers	End of study (Up to 6 months post-intervention)	Tolerability of the study day diet and the oral isotope tracer, primarily gastrointestinal tolerability will be obtained by recording the number of participants with absence of adverse events related to study day diets or nonradioactive isotope tracers.

Trial Locations

Locations (1)

Emory University Hospital; 🇺🇸 Atlanta, Georgia, United States