{"topic_id":"companion_breed_health_arab_horse_omia4491_horse","category":"companion-breed-health","context":"---\nlicense: permission_granted\ntopic_id: companion_breed_health_arab_horse_omia4491_horse\ncategory: companion-breed-health\ntitle: \"Arab (Horse) — Myopathy, myofibrillar (hereditary; OMIA-verified breed predisposition)\"\nlang: en\nsource: \"OMIA (Online Mendelian Inheritance in Animals, University of Sydney) breed-specific hereditary-disorder record, saved verbatim to source_file; C1 substring-verified. Pulled 2026-08-23 from local OMIA database dump.\"\nsource_file: pdf-raw/breed-health/arab_horse_omia4491_4491.txt\ndate_parsed: 2026-08-23\ntokens_estimated: 360\nverification:\n  method: substring_match\n  claims: 6\n  passed: 6\n  date: 2026-08-23\nrecovered: false\npath: companion-breed-health/companion_breed_health_arab_horse_omia4491_horse/01_companion_breed_health_arab_horse_omia4491_horse.md\nsource_document: \"OMIA — Online Mendelian Inheritance in Animals (University of Sydney)\"\ncitation:\n  authority: \"OMIA — Online Mendelian Inheritance in Animals (University of Sydney)\"\n  title: \"Arab (Horse) — Myopathy, myofibrillar (hereditary; OMIA-verified breed predisposition)\"\n  url: \"https://omia.org/OMIA002330/9796/\"\n  retrieved: \"2026-08-23\"\n  ref: \"OMIA breed-specific hereditary-disorder records (omia.org), derived from local OMIA database dump; dataset: https://doi.org/10.25910/2AMR-PV70\"\n  doc_type: \"academic animal-genetics database (breed-specific disorder entries)\"\n  needs_review: false\n\nverification_derived:\n  method: derived_from_dataset\n  source: \"OMIA database dump (omia.xml, local); fields Gene/Variant/Article/OMIM\"\n  note: \"Structured fields (gene, variant rsID/protein change, PubMed/DOI references, OMIM cross-link) extracted from OMIA dump and presented with first-hand values; not verbatim prose.\"---\n\n# Arab (Horse) — Myopathy, myofibrillar (hereditary; OMIA-verified breed predisposition)\n\nSource: first-hand OMIA (University of Sydney) breed-specific hereditary-disorder record, saved verbatim to `source_file`; every claim below is a C1 byte-substring of it.\n\n## Claims\n\n- `Breed: Arab (Horse)`\n- `Disorder: `\n- `Mode of inheritance: Williams et al. (2020): .. a potential familial basis for MFM has been suggested by the presence of desmin aggregates in a 3‐generation family of WB [Valberg et al. 2017].`\n- `Clin feat: Williams et al. (2020): Clinical signs associated with MFM WB are usually apparent by 11 years of age and include exercise intolerance, a reluctance to move forward under saddle and a mild lameness not attributable to an underlying orthopaedic cause.`\n- `Defect: yes`\n- `Pathology: Valberg et al. (2017): Abnormal aggregates of the cytoskeletal protein desmin were found in up to 120 type 2a and a few type 2x myofibres of MFM cases. Desmin positive fibres did not stain for developmental myosin, α actinin or dystrophin. Scores for internalised myonuclei (score MFM 0.83 ± 0.67, controls 0.22 ± 0.45), anguloid atrophy (MFM 0.95 ± 0.55, controls 0.31 ± 0.37) and total myopathic scores (MFM 5.85 ± 2.10, controls 1.41 ± 2.17) were significantly higher in MFM cases vs. controls. Focal Z disc degeneration, myofibrillar disruption and accumulation of irregular granular material was evident in MFM cases. Muscle glycogen concentrations were similar between MFM cases and controls. In the Warmblood family, desmin positive aggregates were found in myofibres of the founding dam and in horses from two subsequent generations.`\n## Associated gene(s)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- OMIA entry symbol: MFM (no structured Phene_Gene link)\n- OMIA molecular-genetics note: Williams et al. (2020): \"Variants identified in MFM candidate genes, including two coding variants offered as commercial MFM equine genetic tests, did not associate with the WB MFM phenotype.\"\n\n## Evidence (references)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- 2017. Clinical characteristics and muscle glycogen concentrations in warmblood horses with polysaccharide storage myopathy. Am J Vet Res — PubMed:PMID29076373 | DOI:10.2460/ajvr.78.11.1305 — OMIA Phene_Article / Article\n- 2018. Muscle glycogen concentrations and response to diet and exercise regimes in Warmblood horses with type 2 Polysaccharide Storage Myopathy. PLoS One — PubMed:PMID30183782 | DOI:10.1371/journal.pone.0203467 — OMIA Phene_Article / Article\n- 2017. Clinical and histopathological features of myofibrillar myopathy in Warmblood horses. Equine Vet J — PubMed:PMID28543538 | DOI:10.1111/evj.12702 — OMIA Phene_Article / Article\n- 2021. Candidate gene expression and coding sequence variants in Warmblood horses with myofibrillar myopathy. Equine Vet J — PubMed:PMID32453872 | DOI:10.1111/evj.13286 — OMIA Phene_Article / Article\n- 2021. Integrated proteomic and transcriptomic profiling identifies aberrant gene and protein expression in the sarcomere, mitochondrial complex I, and the extracellular matrix in Warmblood horses with myofibrillar myopathy. BMC Genomics — PubMed:PMID34112090 | DOI:10.1186/s12864-021-07758-0 — OMIA Phene_Article / Article\n- 2023. Absence of myofibrillar myopathy in Quarter Horses with a histopathological diagnosis of type 2 polysaccharide storage myopathy and lack of association with commercial genetic tests. Equine Vet J — PubMed:PMID35288976 | DOI:10.1111/evj.13574 — OMIA Phene_Article / Article\n- 2025. Myofibrillar myopathy. Vet Clin North Am Equine Pract — PubMed:PMID39880730 | DOI:10.1016/j.cveq.2024.11.005 — OMIA Phene_Article / Article\n- 2025. Sporadic and recurrent exertional rhabdomyolysis. Vet Clin North Am Equine Pract — PubMed:PMID39880734 | DOI:10.1016/j.cveq.2024.11.003 — OMIA Phene_Article / Article\n\n## Comparative medicine (human OMIM)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- OMIM:603689 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:601419 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:617114 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:609200 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:609524 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:619040 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:609452 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:612954 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:613869 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:608810 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:617258 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:619178 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n","sources":["companion-breed-health — Arab (Horse) — Myopathy, myofibrillar (hereditary; OMIA-verified breed predisposition)"],"source":{"authority":"companion-breed-health","title":"Arab (Horse) — Myopathy, myofibrillar (hereditary; OMIA-verified breed predisposition)","url":"https://pubmed.ncbi.nlm.nih.gov/29076373/","retrieved":"","ref":"PMID 29076373","doc_type":"official source","source_document":"","verification_file":""},"source_document":"","source_file":"","trust":{"authority_tier":"ungraded","fidelity":"verbatim","license":null,"display_grade":"pending"},"tokens_estimated":1141,"generated_at":null,"tip":"Use /api/v1/topics to discover more topics. /api/v1/nutrient for precise single-point queries. /api/v1/cross_compare for 2-3 standard comparisons."}