An observational study in Urea Cycle Disorder, sponsored by St. Jude Children's Research Hospital. Recruiting at 1 site in United States. Open to participants aged 16 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-31.
Sponsored by St. Jude Children's Research Hospital · Observational
This study is being done to understand how the brain works while people with urea cycle disorder (UCD) perform driving tasks that range from easy to difficult and to look at how that compares to traditional tests of thinking and attention.
Primary Objective
Secondary Objective
This is a non-therapeutic, non-interventional study in which brain fNIRS (functional near-infrared spectroscopy) measures will be compared under simulated driving conditions between patients with UCD vs. age and sex-matched control participants.
Participants who agree to participate will have Information about their medical history collected, have a basic neurological exam and answer questions about their health, diet, and driving habits. They will complete some simple thinking and memory tests. These tests will help investigators understand skills like memory, attention, and problem-solving. Participants will also wear a soft cap with small sensors called an fNIRS (functional near-infrared spectroscopy) device while they complete a driving simulator activity. This cap is noninvasive and measures how the brain uses oxygen while they drive in the simulator.
All study activities will be completed on the day of enrollment.
66 studies on the registry are indexed under Urea Cycle Disorders, Inborn; 14 are open to participants now.
This study's planned enrollment of 60 is above the median of 46 across 23 observational studies indexed under Urea Cycle Disorders, Inborn.
Browse Urea Cycle Disorders, Inborn studies →St. Jude Children's Research Hospital is the lead sponsor of 440 studies on the registry; 102 are open to participants now.
Of its 61 completed or terminated interventional studies of FDA-regulated products, 37 (61%) have results posted.
Counted across the registry records on this site, refreshed daily.
Individuals who meet the Eligibility Criteria and agree to participate.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Participants with urea cycle disorders (UCD) who meet the Eligibility Criteria and consent to participate
Healthy controls who meet the Eligibility Criteria and consent to participate
Changes in Oxyhemoglobin (HbO), Deoxyhemoglobin (HbR) and Total Hemoglobin (HbT) concentrations in the right and left prefrontal cortex in participants with urea cycle disorders (UCD) compared to healthy control volunteers
Investigators will compare prefrontal cortex hemoglobin concentrations during low cognitive load between patients with UCD and healthy age and sex matched control participants using functional near-infrared spectroscopy (fNIRS). Mean values of hemoglobin concentration differences on the right and left prefrontal cortex between individuals, with and without UCD, during the low cognitive load task will be calculated and compared using two sample t-tests (for normally distributed data) or Wilcoxon rank sum tests (for nonnormally distributed data). P values will be adjusted for multiple comparisons using the Bonferroni method.
Time frame: Day 1, during driving simulator task
Changes in HbO, HbR and HbT concentrations in the left and right parietal and occipital brain regions in participants with urea cycle disorders (UCD) compared to healthy control volunteers
Investigators will compare left and right parietal and occipital regions hemoglobin concentrations during low cognitive load between patients with UCD and healthy age and sex matched control participants using functional near-infrared spectroscopy (fNIRS). Mean values of hemoglobin concentration differences on the left and right parietal and occipital regions between individuals, with and without UCD, during the low cognitive load task will be calculated and compared using two sample t-tests (for normally distributed data) or Wilcoxon rank sum tests (for nonnormally distributed data). P values will be adjusted for multiple comparisons using the Bonferroni method.
Time frame: Day 1, during driving simulator task
Started Jul 2026 (actual). Primary completion is estimated for Aug 2031, 61 months after the start.
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Urea Cycle Disorders, Inborn →
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