Impact of Phenylalanine Elevations on Brain and Cognition in Adult PKU Carriers

The goal of this clinical trial is to advance our understanding of the cognitive and neurophysiologic sequelae associated with suboptimal phenylalanine (Phe) metabolism in heterozygous carriers of phenylketonuria (PKU). The main questions it aims to answer are: * Do PKU carriers experience prolonged elevations in brain Phe levels following oral ingestion of dietary Phe? * Do PKU carriers experience disruptions in cognitive functioning following oral ingestion of dietary Phe? * Do PKU carriers experience atypical brain activity following oral ingestion of dietary Phe? Researchers will compare PKU carriers and non-carriers following oral ingestion of dietary Phe and a placebo. Participants will: * Consume Phe or a placebo at two separate visits to our facility * At each visit, they will complete a series of MRIs and cognitive tests throughout the day

NCT Number	NCT07220265
Lead Sponsor	University of Missouri-Columbia Collaborators: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Conditions	Carrier of Phenylketonuria, Healthy
Enrollment	36 participants
Start Date	2025-12-19
Primary Completion	2026-12-31 (estimated)
Study Completion	2026-12-31 (estimated)
Updated on ClinicalTrials.gov	2026-03-11