Protein Requirements in Children With Phenylketonuria (PKU)

Study Overview
=================
Brief Summary
-----------------
Phenylketonuria (PKU) is an inherited inborn error of an amino acid phenylalanine (PHE) metabolism affecting 1:15,000 births. It is caused by a decreased activity of an enzyme in the liver called phenylalanine hydroxylase (PAH) which is important to convert PHE into tyrosine, another amino acid. Consequently, PHE accumulates in the blood leading to mental and developmental delays. Nutritional management is the primary choice of treatment that includes providing sufficient protein in the diet and at the same time restricting PHE. However the amount of protein to be given is unknown. A new technique called Indicator Amino Acid Oxidation (IAAO) will be used to determine the protein requirements in children with PKU (5-18y). The study will help treat and manage these children with sufficient protein to ensure proper growth and development. Current dietary recommendations range from 35-65 g/day and is based on factorial calculations. The investigators hypothesize that the protein requirement in children with PKU will be higher than the current mathematically calculated recommended intake of 35-65 g/day for the 5-18y children.

Official Title
-----------------
Application of Stable Isotopes to Determine Protein Requirements in Children With Phenylketonuria (PKU)

Conditions
-----------------
Phenylketonuria

Intervention / Treatment
-----------------
* Dietary Supplement: Protein intake


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Children (5-18y) who are diagnosed with Phenylketonuria (PKU), and clinically stable with no acute illness Exclusion Criteria: Children less than 5y of age and who are diagnosed with PKU, as it may be difficult to take breath samples and perform indirect calorimetry in very young children. Children diagnosed with PKU, but are currently ill, with a fever, cold, vomiting or diarrhea.

Ages Eligible for Study
-----------------
Minimum Age: 5 Years
Maximum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Protein intake<br>Protein intake- Dietary supplement | Dietary Supplement: Protein intake<br>* Oral consumption of eight hourly experimental meals- 4 tracer free experimental meals containing a mixture of free amino acids and calories from protein free flavored liquid, protein free cookies and corn oil 4 isotopically labeled experimental meals.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 13 Co2 production | Urine and breath samples will be collected during the study to measure the rate of oxidation of tracer in the expired breath and flux enrichment in urine. | 8 hours (1 study day) | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Phenylketonuria, PKU, Phenylalanine metabolism, Protein requirements, Indicator Amino acid Oxidation, Stable isotopes