Phenylketonuria and Hyperphenylalaninemia Nutrition Study

University of Zurich30 enrolled

Overview

The mainstay of PKU treatment is a low-phenylalanine diet (i.e restriction of natural protein), and supplementation with a protein substitute (a mixture of amino acids free from phenylalanine, also containing micronutrients and vitamins) and special low-protein foods, to meet the patient's energy requirements. When diet and treatment is relaxed after childhood, adult and adolescent patients with phenylketonuria are at risk for malnutrition, depending on the compliance with treatment and the intake of amino acid supplements. In this study, nutrition status of patients with PKU and hyperphenylalaninemia is systematically assessed under ongoing current treatment, in relation to Phe-tolerance, compliance with treatment, and psychosocial issues. Study participants do not undergo any specific therapeutic or diagnostic intervention.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Phenylketonuria (PKU) and Hyperphenylalaninemia

Interventions

PROCEDURE

Eligibility

Outcomes

Primary Outcomes

Macronutrient and micronutrient intake, calculated from a nutrition protocol (four consecutive days)

Assessed nutrients: Macronutrients: protein, fat, carbohydrates in g/kg/d Daily phenylalanine and tyrosine intake Micronutrients and minerals: Calcium, magnesium, iron, zinc, selenium Vitamins: D, B12, B6, C, folic acid

Time frame: assessed during 4 consecutive days max. within 1 month after a regular consultation in the outpatient clinic

Secondary Outcomes

Phenylalanine level (umol/l)

this outcome measure is not study-specific and is collected as part of established routine care (self-measurement by patient)

Time frame: assessed at the end of the four-day nutrition protocol (see primary outcome)

Plasma amino acid profile

this outcome measure is not study-specific and is collected as part of established routine care.

Time frame: determined at a routine visit at the outpatient clinic, on average 1x per year

Concentrations of micronutrients, minerals and vitamins

assessed parameters: Ferritin, zinc, selenium, vitamin D, vitamin B12, folic acid. These outcome measures are not study-specific and are collected as part of established routine care

Time frame: determined at a routine visit at the outpatient clinic, on average 1x per year

body weight (kg)

assessed as part of routine clinical care

Time frame: determined at a routine visit at the outpatient clinic, on average once every 6 - 12 months