{"id":"e0fc0cfa-2571-58d2-976b-20cef18fe16d","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-mma-folate-renal-confounding","predicate":"elevation_is_not_specific_for","statement":"MMA was elevated in 12.2% of the folate-deficient group; all but one were attributed to renal insufficiency or hypovolemia.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"5b5b33cd-a2f7-5dbb-bae8-afb84cafa401","mechanism_event_label":"An abnormal MMA result needs its clinical and kidney context.","subject":{"id":"a2fda496-9308-54c5-b478-bc0b0c175570","slug":"methylmalonic-acid","display_name":"Methylmalonic acid","entity_type_key":"small_molecule"},"object":{"id":"ed0ea8da-9ffb-51b2-8a98-96cbf4fc919d","slug":"b12-deficiency-diagnosis","display_name":"B12 deficiency diagnosis","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"5b5b33cd-a2f7-5dbb-bae8-afb84cafa401","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-mma-folate-renal-confounding-event","event_type":"observed_intervention","label":"An abnormal MMA result needs its clinical and kidney context.","description":"MMA was elevated in 12.2% of the folate-deficient group; all but one were attributed to renal insufficiency or hypovolemia.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a2fda496-9308-54c5-b478-bc0b0c175570","slug":"methylmalonic-acid","display_name":"Methylmalonic acid","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"ed0ea8da-9ffb-51b2-8a98-96cbf4fc919d","slug":"b12-deficiency-diagnosis","display_name":"B12 deficiency diagnosis","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"Separates a shared diagnostic setting from direct cofactor identity.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Selected clear-cut deficiency series: 434 B12 episodes in 406 patients and 123 folate episodes in 119 patients.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Serum MMA and total homocysteine assays; elevation defined above three standard deviations of the reference mean.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"These are authors’ clinical attributions, not randomized tests of renal causation. Folate does not thereby become the MMUT cofactor.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"An abnormal MMA result needs its clinical and kidney context.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b12-savage1994] Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies (1994). https://pubmed.ncbi.nlm.nih.gov/8154512/ DOI: 10.1016/0002-9343(94)90149-x","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human blood or whole-person endpoints","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"8b368f04-55a2-5b30-8dca-52c76e1b3699","evidence_kind":"source_excerpt","locator":"Lines 1487-1498","start_line":1487,"end_line":1498,"excerpt":"### b12-mma-folate-renal-confounding\nMMA was elevated in 12.2% of the folate-deficient group; all but one were attributed to renal insufficiency or hypovolemia.\nCondition category: biomarker_context\nnutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An abnormal MMA result needs its clinical and kidney context.\norganism: Homo sapiens\ntissue_or_cell_type: Human blood or whole-person endpoints\nexperimental_model: Selected clear-cut deficiency series: 434 B12 episodes in 406 patients and 123 folate episodes in 119 patients.\nlimitations: These are authors’ clinical attributions, not randomized tests of renal causation. Folate does not thereby become the MMUT cofactor.\nexposure: Serum MMA and total homocysteine assays; elevation defined above three standard deviations of the reference mean.\ncross_nutrient: Separates a shared diagnostic setting from direct cofactor identity.\n[b12-savage1994] Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies (1994). https://pubmed.ncbi.nlm.nih.gov/8154512/ DOI: 10.1016/0002-9343(94)90149-x","model_system":"Selected clear-cut deficiency series: 434 B12 episodes in 406 patients and 123 folate episodes in 119 patients.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b12-savage1994] Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies (1994). https://pubmed.ncbi.nlm.nih.gov/8154512/ DOI: 10.1016/0002-9343(94)90149-x","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"73145023-2982-5848-aff2-8d8875d6b9c5","stable_key":"import-7fc92b9e-9cbf-556e-8719-6b5244625250","title":"Vitamin B12: mechanisms, 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":"ad5b3a51d36e856aa7fdfd1cc23f690b094689bad87d28e1a621a54675a01c92","revision_id":"118bd616-0c13-549f-bfeb-bc439715b89c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}