{"id":"7945243b-ee97-56ed-a08e-98a4cce4a46e","stable_key":"6cdb37aa-8998-5ea8-829d-4f995caf98fc:l-carnitine-cact-loss","predicate":"variant_reduces","statement":"The human SLC25A20 p.Arg133Trp substitution impaired carrier activity after bacterial expression and liposome reconstitution.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"dd366d7f-6671-5059-b7a5-367f8b3d16c7","mechanism_event_label":"A second transport defect can block the mitochondrial shuttle even when carnitine exists.","subject":{"id":"b52f80b3-1b03-58ef-aa42-f321bdaead31","slug":"human-slc25a20","display_name":"Human carnitine-acylcarnitine translocase / SLC25A20","entity_type_key":"protein"},"object":{"id":"8bc40b95-3247-580f-b2c0-0f12bf4a01ab","slug":"human-cact-transport-activity","display_name":"Human CACT carnitine transport activity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"dd366d7f-6671-5059-b7a5-367f8b3d16c7","stable_key":"6cdb37aa-8998-5ea8-829d-4f995caf98fc:l-carnitine-cact-loss-event","event_type":"observed_relationship","label":"A second transport defect can block the mitochondrial shuttle even when carnitine exists.","description":"The human SLC25A20 p.Arg133Trp substitution impaired carrier activity after bacterial expression and liposome reconstitution.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b52f80b3-1b03-58ef-aa42-f321bdaead31","slug":"human-slc25a20","display_name":"Human carnitine-acylcarnitine translocase / SLC25A20","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"8bc40b95-3247-580f-b2c0-0f12bf4a01ab","slug":"human-cact-transport-activity","display_name":"Human CACT carnitine transport activity","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"f1c881ce-8094-5602-bb97-074377340185","slug":"palmitoylcarnitine","display_name":"Palmitoyl-L-carnitine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Functional variant study within a six-patient CACT-deficiency report.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"CACT deficiency is distinct from OCTN2 deficiency; supplying substrate does not replace a transporter.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Carnitine collection; isomer, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A second transport defect can block the mitochondrial shuttle even when carnitine exists.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Molecular and functional analysis of SLC25A20 mutations causing carnitine-acylcarnitine translocase deficiency. · 2004 · https://pubmed.ncbi.nlm.nih.gov/15365988/ · DOI 10.1002/humu.20085","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"c4f93c87-a2e4-5368-bc28-cea7f3e0d6e6","evidence_kind":"source_excerpt","locator":"Lines 122-128","start_line":122,"end_line":128,"excerpt":"## l-carnitine-cact-loss\nA second transport defect can block the mitochondrial shuttle even when carnitine exists.\nThe human SLC25A20 p.Arg133Trp substitution impaired carrier activity after bacterial expression and liposome reconstitution.\nModel: Functional variant study within a six-patient CACT-deficiency report.\nLimitations: CACT deficiency is distinct from OCTN2 deficiency; supplying substrate does not replace a transporter.\nEvidence access: Primary abstract\nMolecular and functional analysis of SLC25A20 mutations causing carnitine-acylcarnitine translocase deficiency. · 2004 · https://pubmed.ncbi.nlm.nih.gov/15365988/ · DOI 10.1002/humu.20085","model_system":"Functional variant study within a six-patient CACT-deficiency report.","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":"e2c9c42b-806a-55e2-abde-b0320ea94704","stable_key":"import-6cdb37aa-8998-5ea8-829d-4f995caf98fc","title":"L-Carnitine: synthesis, acyl-group transport, fuel selection and nutrient interactions (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. 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