{"topic_id":"companion_breed_health_domestic_shorthair_omia2514_cat","category":"companion-breed-health","context":"---\nlicense: permission_granted\ntopic_id: companion_breed_health_domestic_shorthair_omia2514_cat\ncategory: companion-breed-health\ntitle: \"Domestic Shorthair — Myotonia (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 2026-08-02 from local OMIA database dump.\"\nsource_file: pdf-raw/breed-health/domestic_shorthair_omia2514_2514.txt\ndate_parsed: 2026-08-02\ntokens_estimated: 372\nverification:\n  method: substring_match\n  claims: 6\n  passed: 6\n  date: 2026-08-02\nrecovered: false\npath: companion-breed-health/companion_breed_health_domestic_shorthair_omia2514_cat/01_companion_breed_health_domestic_shorthair_omia2514_cat.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: \"Domestic Shorthair — Myotonia (hereditary; OMIA-verified breed predisposition)\"\n  url: \"https://omia.org/OMIA000698/9685/\"\n  retrieved: \"2026-08-02\"\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\n\n# Domestic Shorthair — Myotonia (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: Domestic Shorthair (Cat)`\n- `Disorder: `\n- `Mode of inheritance: Probably autosomal recessive`\n- `Clin feat: Clinically, myotonic cats usually have muscle hypertrophy with dimpling after percussion and may appear poorly groomed. Affected cats demonstrate blepharospasm upon testing the palpebral reflex and menace response but have normal mentation. They ambulate with an abnormally short stride and stiff, choppy gait, restricted limb adduction, and they may stiffen and fall in lateral recumbency when startled. Clinical presentation may also include a limited ability to open the jaws, dysphonia, dysphagia, facial spasms, a protruding hypertrophic tongue, and varying degrees of gingivitis and dental disease. (Toll et al., 1998; Gaschen et al., 2004; Gandolfi et al., 2014) Electromyography of these animals demonstrates classical myotonic discharges, seen as repetitive spontaneous “waxing and waning” discharges (Toll et al., 1998; Gaschen et al., 2004). Some cats have been reported to develop respiratory stridor and cyanosis when stressed by handling (Toll et al., 1998). IT thanks DVM student Alexandrea Costanza, who provided the basis of this contribution in May 2023.`\n- `Defect: yes`\n- `Pathology: Muscle histopathology reveals hypertrophy of all muscle fibre types (Hickford et al., 1998; Gandolfi et al., 2014). IT thanks DVM student Alexandrea Costanza, who provided the basis of this contribution in May 2023.`\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- Gene: Entrez Gene ID 389719640 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene\n- OMIA molecular-genetics note: Using the candidate gene approach, Gandolphi et al. (2014) identified a likely causal mutation (omia.variant:408) as a \"c.1930+1G&gt;T transversion [that] altered the 5′ splice site at the junction of exon 16 and intron 16\" of <em>CLCN1. </em>These same authors also reported that \"In silico translation of the altered transcript predicts the lack of 116 amino acids, from residues 557 to residue 643…\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- 1998. Congenital myotonia in 2 domestic cats. Journal of Veterinary Internal Medicine — PubMed:PMID9560769 — OMIA Phene_Article / Article\n- 1998. Congenital myotonia in related kittens. Journal of Small Animal Practice — PubMed:PMID9673904 — OMIA Phene_Article / Article\n- 1998. Feline congenital myotonia. Journal of Small Animal Practice — PubMed:PMID9816575 — OMIA Phene_Article / Article\n- 2004. Congenital diseases of feline muscle and neuromuscular junction. J Feline Med Surg — PubMed:PMID15546767 | DOI:10.1016/j.jfms.2004.02.003 — OMIA Phene_Article / Article\n- 2014. A novel mutation in CLCN1 associated with feline myotonia congenita. PLoS One — PubMed:PMID25356766 | DOI:10.1371/journal.pone.0109926 — OMIA Phene_Article / Article\n- 2022. Genetic epidemiology of blood type, disease and trait variants, and genome-wide genetic diversity in over 11,000 domestic cats. PLoS Genet — PubMed:PMID35709088 | DOI:10.1371/journal.pgen.1009804 — OMIA Phene_Article / Article\n- 2022. A novel mutation of the CLCN1 gene in a cat with myotonia congenita: Diagnosis and treatment. J Vet Intern Med — PubMed:PMID35815860 | DOI:10.1111/jvim.16471 — OMIA Phene_Article / Article\n- 2023. Hereditary myotonia in cats associated with a new homozygous missense variant p.Ala331Pro in the muscle chloride channel ClC-1. J Vet Intern Med — PubMed:PMID37668104 | DOI:10.1111/jvim.16837 — OMIA Phene_Article / Article\n- 2024. Development and validation of animal variant classification guidelines to objectively evaluate genetic variant pathogenicity in domestic animals. Front Vet Sci — PubMed:PMID39703406 | DOI:10.3389/fvets.2024.1497817 — 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:160800 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:255700 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:118425 (type: gene) — OMIA Group_OMIM (via OMIA_ID)\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","sources":["companion-breed-health — Domestic Shorthair — Myotonia (hereditary; OMIA-verified breed predisposition)"],"source":{"authority":"companion-breed-health","title":"Domestic Shorthair — Myotonia (hereditary; OMIA-verified breed predisposition)","url":"https://pubmed.ncbi.nlm.nih.gov/9560769/","retrieved":"","ref":"PMID 9560769","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":1064,"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."}