{"id":"b37e8b86-58f1-5b31-a8d7-b73aa5595d9d","stable_key":"08ce9896-9d1c-5bbf-b705-5bfe771091d5:b7-carnitine-hides-c5oh","predicate":"low_availability_masks","statement":"Combined biotin and carnitine deficiency largely masked the increase in substrate-derived acylcarnitines observed with isolated biotin deficiency in HepG2 cells.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"b21f9111-de5a-5e47-8037-3df4444da0bd","mechanism_event_label":"A second shortage can hide the laboratory signature of the first.","subject":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"object":{"id":"704c380c-9902-516d-8919-eb6e2b58a065","slug":"hepg2-c5oh","display_name":"HepG2 3-hydroxyisovalerylcarnitine pool","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"b21f9111-de5a-5e47-8037-3df4444da0bd","stable_key":"08ce9896-9d1c-5bbf-b705-5bfe771091d5:b7-carnitine-hides-c5oh-event","event_type":"biochemical_relationship","label":"A second shortage can hide the laboratory signature of the first.","description":"Combined biotin and carnitine deficiency largely masked the increase in substrate-derived acylcarnitines observed with isolated biotin deficiency in HepG2 cells.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"37a8e96b-f95b-5ba7-a0bc-8ed3cfaf5fd8","slug":"biotin","display_name":"Biotin","entity_type_key":"small_molecule"},"role":"coexisting restricted nutrient","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"8f222f3c-c671-52e4-bde5-1093e56ad486","slug":"3-hydroxyisovalerylcarnitine","display_name":"3-Hydroxyisovalerylcarnitine / 3-HIA-carnitine","entity_type_key":"small_molecule"},"role":"masked marker","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":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"704c380c-9902-516d-8919-eb6e2b58a065","slug":"hepg2-c5oh","display_name":"HepG2 3-hydroxyisovalerylcarnitine pool","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/biotin-research/25527659.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f\", \"start_char\": 0, \"end_char\": 2372, \"text_sha256\": \"4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Two-factor biotin/carnitine depletion and carnitine repletion in human HepG2 cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Separate and combined biotin and carnitine depletion","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This is a cell-culture demonstration of marker masking; it does not validate a diagnostic correction formula in pregnancy or the general population.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Biotin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"biotin","display_name":"Biotin","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A second shortage can hide the laboratory signature of the first.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b7-p25527659] In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency. (2015). https://pubmed.ncbi.nlm.nih.gov/25527659/ DOI: 10.3945/jn.114.201343","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"HepG2 hepatoma cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"bc354d59-54fa-534d-b99f-8a460b354ac3","evidence_kind":"source_excerpt","locator":"Lines 962-973","start_line":962,"end_line":973,"excerpt":"### b7-carnitine-hides-c5oh\nCombined biotin and carnitine deficiency largely masked the increase in substrate-derived acylcarnitines observed with isolated biotin deficiency in HepG2 cells.\nCondition category: nutrient_deficiency\nnutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A second shortage can hide the laboratory signature of the first.\norganism: Homo sapiens\ntissue_or_cell_type: HepG2 hepatoma cells\nexperimental_model: Two-factor biotin/carnitine depletion and carnitine repletion in human HepG2 cells\nlimitations: This is a cell-culture demonstration of marker masking; it does not validate a diagnostic correction formula in pregnancy or the general population.\nexposure: Separate and combined biotin and carnitine depletion\nevidence_span: {\"source_cache\": \"artifacts/biotin-research/25527659.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f\", \"start_char\": 0, \"end_char\": 2372, \"text_sha256\": \"4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f\"}\n[b7-p25527659] In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency. (2015). https://pubmed.ncbi.nlm.nih.gov/25527659/ DOI: 10.3945/jn.114.201343","model_system":"Two-factor biotin/carnitine depletion and carnitine repletion in human HepG2 cells","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b7-p25527659] In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency. (2015). https://pubmed.ncbi.nlm.nih.gov/25527659/ DOI: 10.3945/jn.114.201343","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"9608806b-adb6-5a35-b042-057147135642","stable_key":"import-08ce9896-9d1c-5bbf-b705-5bfe771091d5","title":"Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"a05b23a45e0813ba2fcda0027e3f5d9d58b82858f8dd8598ffb7aca17e942a38","revision_id":"e0d0c2a2-e9e2-55dd-b467-41c22ba960d4","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}