{"id":"a541bf05-69bc-5799-b0fc-749ef7d0a7ff","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-sapropterin-tolerance","predicate":"increases","statement":"In 46 preselected sapropterin-responsive children, 20 mg/kg/day allowed more supplemental dietary phenylalanine while maintaining study blood targets: 20.9 versus 2.9 mg/kg/day with placebo.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"1c6aa219-5ca5-5e04-8445-4f50f15ff933","mechanism_event_label":"When processing capacity improves, a responsive patient may tolerate more dietary phenylalanine.","subject":{"id":"0ea697b5-afbd-5aa7-b916-99c33f7eaf30","slug":"sapropterin","display_name":"Sapropterin, pharmaceutical tetrahydrobiopterin","entity_type_key":"drug"},"object":{"id":"a14f3561-5f2f-5522-a1bf-520254f74edb","slug":"pku-dietary-phenylalanine-tolerance","display_name":"Dietary phenylalanine tolerance in responsive PKU children","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"1c6aa219-5ca5-5e04-8445-4f50f15ff933","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-sapropterin-tolerance-event","event_type":"observed_relationship","label":"When processing capacity improves, a responsive patient may tolerate more dietary phenylalanine.","description":"In 46 preselected sapropterin-responsive children, 20 mg/kg/day allowed more supplemental dietary phenylalanine while maintaining study blood targets: 20.9 versus 2.9 mg/kg/day with placebo.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"0ea697b5-afbd-5aa7-b916-99c33f7eaf30","slug":"sapropterin","display_name":"Sapropterin, pharmaceutical tetrahydrobiopterin","entity_type_key":"drug"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"a14f3561-5f2f-5522-a1bf-520254f74edb","slug":"pku-dietary-phenylalanine-tolerance","display_name":"Dietary phenylalanine tolerance in responsive PKU children","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"ea908671-6f85-5342-abe4-1a466a3b0572","slug":"pah","display_name":"Human phenylalanine hydroxylase / PAH","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Ten-week randomized trial after responder selection.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Selected pediatric responders cannot represent all PKU patients.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Phenylalanine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"When processing capacity improves, a responsive patient may tolerate more dietary phenylalanine.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Efficacy of sapropterin dihydrochloride in increasing phenylalanine tolerance in children with phenylketonuria: a phase III, randomized, double-blind, placebo-controlled study. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19261295/ · DOI 10.1016/j.jpeds.2008.11.040","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"039d8bf2-b962-5268-a067-750a33d50e73","evidence_kind":"source_excerpt","locator":"Lines 230-236","start_line":230,"end_line":236,"excerpt":"## l-phenylalanine-sapropterin-tolerance\nWhen processing capacity improves, a responsive patient may tolerate more dietary phenylalanine.\nIn 46 preselected sapropterin-responsive children, 20 mg/kg/day allowed more supplemental dietary phenylalanine while maintaining study blood targets: 20.9 versus 2.9 mg/kg/day with placebo.\nModel: Ten-week randomized trial after responder selection.\nLimitations: Selected pediatric responders cannot represent all PKU patients.\nEvidence access: Primary abstract\nEfficacy of sapropterin dihydrochloride in increasing phenylalanine tolerance in children with phenylketonuria: a phase III, randomized, double-blind, placebo-controlled study. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19261295/ · DOI 10.1016/j.jpeds.2008.11.040","model_system":"Ten-week randomized trial after responder selection.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"54de7c56-1e60-5d7b-8ef9-852c58ae92ba","stable_key":"import-56f1d914-e7da-595a-af69-c217b2b47407","title":"L-Phenylalanine: transport, protein synthesis, cofactor recycling and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"4d53adcd4acc7a9aecf44ccb2623ec540c9d221a0f7c00002585870b39b8ffb8","revision_id":"fd182a81-4ab7-559a-9c77-fb4cf72982ef","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}