Understanding Phenylalanine's Impact on Brain and Cognition in PKU Carriers
This study aims to understand how elevated phenylalanine (Phe) levels affect the brain and thinking abilities in adults who are carriers of Phenylketonuria (PKU). Researchers will compare PKU carriers with healthy individuals who are not carriers. You would receive either phenylalanine (a dietary supplement) or a placebo (Vitamin C). The study will look at your blood and brain phenylalanine levels, and how your brain activity and thinking skills change after taking the supplement or placebo. This will help us learn if PKU carriers experience prolonged high brain Phe levels or changes in thinking after consuming Phe. The study plans to enroll 36 participants, but its current status is unclear.
- Study design
- This is an interventional study involving 36 participants, including both PKU carriers and non-carriers. It is a double-blind crossover study, meaning neither you nor the researchers will know if you are receiving phenylalanine or placebo at a given time.
- What's involved
- You would have blood and brain phenylalanine levels measured at three timepoints: before taking the supplement/placebo, and then 2 and 4 hours after. You would also perform cognitive tests and brain scans (fMRI) at these same timepoints.
- Compensation
- Not stated in the trial record.
- Follow-up
- Your blood and brain levels, and cognitive function, will be assessed up to 4 hours after taking the phenylalanine or placebo.
AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.
Impact of Phenylalanine Elevations on Brain and Cognition in Adult PKU Carriers
At a glance
Conditions
Where it's being run
1 sites across 1 statesWho to contact
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What this trial measures
- Blood Phenylalanine Levels3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
- Brain Phenylalanine Levels3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Brain Phenylalanine Levels estimated using magnetic resonance spectroscopy (MRS)
- Brain Phenylalanine-to-Tyrosine Ratio3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Ratio of Phenylalanine-to-Tyrosine concentrations in the brain as estimated using magnetic resonance spectroscopy (MRS)
- Neural Activity during Go/No-Go Task3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Pattern of brain activation as captured using functional MRI while performing a go/no-go inhibitory task
- Operational Span Task3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Performance-based measure of working memory ability. In this task, participants first solve a math problem and then see a letter, and then solve another math problem, and see another letter. This math-letter sequence is repeated from three to seven times for each trial with an unpredictable length each time. After each math-letter sequence, participants are asked to recall, in order, the preceding letters. Scores are calculated by summing the number of letters correctly recalled in the correct order.
- Multi-Source Interference Task3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Performance-based measure of focused attention. ). In this task, participants are shown a display containing three horizontally-aligned numbers (i.e., 1, 2, or 3) and asked to respond as quickly as possible to the location (position #1, 2, or 3) of the number stimulus that is different from the others. The location may be congruent (e.g., "323") or incongruent (e.g., "112") with identity of the target number. Mean response time and error rate will served as the outcome variables.
- Grooved Pegboard Test3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Performance-based measure of processing speed \& fine motor control
- Resting-State Functional Connectivity3 timepoints: baseline (pre-load), 2 hours and 4 hours after starting oral administration of Phe or placebo
Synchronization of neural activity within brain networks as measured by functional MRI while participants are at rest