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Purpose

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.

Condition

Eligibility

Eligible Ages
Over 18 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

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

Phase
N/A
Study Type
Interventional
Allocation
N/A
Intervention Model
Single Group Assignment
Intervention Model Description
The Primary purpose of this study is focused on Translational Science. The study will determine the protein requirements in one group of participants with PKU, based on genotype and medical food consumption, using the IAAO method.
Primary Purpose
Other
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Adults with PKU receiving test diet and Oral stable nonradioactive isotope provision 		Participants will receive amino acid tracer (Oral stable nonradioactive isotope provision) and test diet (medical food) throughout each study day, for a total of 7 study days.
  • Other: Nonradioactive stable oral isotope
    NaH13CO3 [99% atom percent excess (APE) and L-[1-13C]Leu (99% APE) will be given orally. Isotope administration will begin with the fifth meal on each study day with each remaining meal. The nonradioactive stable oral isotope is being administered to study the physiological process of amino acid oxidation.
    Other names:
    • Oral Isotope tracer
  • Other: Test diet
    Test diets will be provided on study days in 8 hourly isocaloric and isonitrogenous meals to maintain a metabolic steady state. Each meal will provide one-twelfth of the participant's daily needs to model a 12-hour fasted and 12-hour fed feeding pattern. The diet will be composed of PFD2 (Mead Johnson), Tang and Kool-Aid (Kraft), corn oil, and protein-free wheat starch cookies. Each participant will receive 1 of 7 test protein intakes (0.2-3.2 g ⋅ kg-1 ⋅ d-1) on each study day. Protein will be provided as a crystalline L-amino acid mixture based on an egg protein pattern. Phe will be provided separately based on the Phe tolerance for each patient established by the metabolic dietitian listed on the IRB protocol. Leucine will be provided at a constant amount of 82.6 mg/kg/day as it is used as the indicator amino acid. The medical food used in this study is being fed to subjects for nutritional purposes to study the oxidation of the nonradioactive oral isotope.
    Other names:
    • Medical Food

Recruiting Locations

Emory University Hospital
Atlanta, Georgia 30322

More Details

Status
Recruiting
Sponsor
Emory University

Study Contact

Jessica Strosahl, PhD, RDN, LD
404-727-1528
jessica.nash.strosahl@emory.edu

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.

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.