--- license: permission_granted topic_id: companion_breed_health_maine_coon_polydactyl_omia3786_cat category: companion-breed-health title: "Maine Coon Polydactyl — Multidrug resistance 1, ABCB1-related (hereditary; OMIA-verified breed predisposition)" lang: en source: "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." source_file: pdf-raw/breed-health/maine_coon_polydactyl_omia3786_3786.txt date_parsed: 2026-08-02 tokens_estimated: 348 verification: method: substring_match claims: 6 passed: 6 date: 2026-08-02 recovered: false path: companion-breed-health/companion_breed_health_maine_coon_polydactyl_omia3786_cat/01_companion_breed_health_maine_coon_polydactyl_omia3786_cat.md source_document: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" citation: authority: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" title: "Maine Coon Polydactyl — Multidrug resistance 1, ABCB1-related (hereditary; OMIA-verified breed predisposition)" url: "https://omia.org/OMIA001402/9685/" retrieved: "2026-08-02" ref: "OMIA breed-specific hereditary-disorder records (omia.org), derived from local OMIA database dump; dataset: https://doi.org/10.25910/2AMR-PV70" doc_type: "academic animal-genetics database (breed-specific disorder entries)" needs_review: false
Maine Coon Polydactyl — Multidrug resistance 1, ABCB1-related (hereditary; OMIA-verified breed predisposition)
Source: 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.
Claims
Breed: Maine Coon Polydactyl (Cat)Disorder:Mode of inheritance: A recessive mode of inheritance has been considered. In other species an incomplete dominant mode of inheritance is discussed.Clin feat: Multidrug resistance 1 results in higher risk of adverse drug reactions to P-glycoprotein substrate drugs such as ivermectin and macrocyclic lactones due to impaired P-glycoprotein synthesis. These drugs are commonly found in flea and tick preventatives for cats and dogs (Mealey et al., 2023). Clinical effects can be neurological such as CNS depression, ataxia, seizure activity, tremors, hypersalivation, vomiting, mydriasis, dyspnoea, and in severe cases, coma, blindness and death. It can also manifest in bone marrow suppression in the form of neutropenia and thrombocytopenia. Gatstrointestinal toxicity has also been reported (Mealey et al., 2021). IT thanks DVM student Wen Yee Tan, who provided the basis of this contribution in May 2023.Defect: yesPrevalence: Mealey et al. (2021): The distribution of genotypes from the banked feline DNA samples was as follows: 0 homozygous for ABCB11930_1931del TC, 47 heterozygous for ABCB11930_1931del TC, and 959 homozygous for the wild-type ABCB1 allele. Among the 47 cats with the mutant ABCB1 allele, only 3 were purebred (Ragdoll, Russian Blue, and Siamese).
Associated gene(s)
Derived 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.
- Gene: ABCB4 (Entrez Gene ID 388257278) — OMIA Phene_Gene / GeneSynonym
- OMIA molecular-genetics note: By sequencing the most obvious functional candidate gene in 8 cats that showed "adverse reactions to P-glycoprotein substrate drugs" (including one sensitive to ivermectin), Mealey and Burke (2015) discovered a 2bp deletion in the <em>ABCB1</em> gene (11930_1931del TC, omia.variant:1322) that was homozygous in the one cat sensitive to ivermectin. However, the other 7 sensitive cats were homozygous…
Evidence (references)
Derived 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.
- 2015. Identification of a nonsense mutation in feline ABCB1. J Vet Pharmacol Ther — PubMed:PMID25660379 | DOI:10.1111/jvp.12212 — OMIA Phene_Article / Article
- 2021. ABCB11930_1931del TC gene mutation in a temporal cluster of macrocyclic lactone-induced neurologic toxicosis in cats associated with products labeled for companion animal use. J Am Vet Med Assoc — PubMed:PMID34125616 | DOI:10.2460/javma.259.1.72 — OMIA Phene_Article / Article
- 2021. Detection of the ABCB11930_1931del TC mutation in two suspected ivermectin-sensitive cats and their relatives by a novel TaqMan allelic discrimination assay. Front Vet Sci — PubMed:PMID35265692 | DOI:10.3389/fvets.2021.808392 — OMIA Phene_Article / Article
- 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
- 2023. Canine and feline P-glycoprotein deficiency: What we know and where we need to go. J Vet Pharmacol Ther — PubMed:PMID36326478 | DOI:10.1111/jvp.13102 — OMIA Phene_Article / Article
- 2023. Assessment of verdinexor as a canine P-glycoprotein substrate. J Vet Pharmacol Ther — PubMed:PMID36924353 | DOI:10.1111/jvp.13123 — OMIA Phene_Article / Article
- 2019. Suspected adverse drug interaction between spinosad and milbemycin oxime in a cat. Journal of Feline Medicine and Surgery 5(1), — OMIA Phene_Article / Article
- 2024. Application of eprinomectin-containing parasiticides at label doses causes neurological toxicosis in cats homozygous for ABCB11930_1931del TC. J Vet Pharmacol Ther — PubMed:PMID38366723 | DOI:10.1111/jvp.13431 — OMIA Phene_Article / Article
- 2024. Relevance of pharmacogenetics and pharmacogenomics in veterinary clinical practice: A review. Anim Genet — PubMed:PMID37990577 | DOI:10.1111/age.13376 — OMIA Phene_Article / Article
- 2025. Avermectin-induced neurotoxicity and mortality reported more commonly in cats homozygous for ABCB11930_1931del TC after application of eprinomectin- versus selamectin-containing products. J Am Vet Med Assoc — PubMed:PMID40738165 | DOI:10.2460/javma.25.05.0304 — OMIA Phene_Article / Article
- 2025. Assessment of clinically relevant drugs as feline P-glycoprotein substrates. Front Vet Sci — PubMed:PMID41133197 | DOI:10.3389/fvets.2025.1668282 — OMIA Phene_Article / Article
- 2025. Functional characterization of the cat and dog wild-type and mutant MDR1 carrier proteins and frequency of the MDR1 gene mutation in 800 cats from Germany. J Vet Pharmacol Ther — PubMed:PMID41474640 | DOI:10.1111/jvp.70041 — OMIA Phene_Article / Article
- (2 additional references in OMIA)
Comparative medicine (human OMIM)
Derived 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.
- OMIM:171050 (type: gene) — OMIA Group_OMIM (via OMIA_ID)
- OMIM:120080 (type: trait) — OMIA Group_OMIM (via OMIA_ID)
verification_derived: method: derived_from_dataset source: "OMIA database dump (omia.xml, local); fields Gene/Variant/Article/OMIM" 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."