MDR1 (Multidrug Resistance 1) Medication Sensitivity
MDR1 (Multidrug Resistance 1) Medication Sensitivity. Autosomal dominant. Observed in 30 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,642 dogs (Donner 2023). Per-dog phenotype outcome depends on penetrance, modifiers, and environment; the carrier frequencies below describe variant prevalence, not disease incidence.
- OMIA identifier
- OMIA:001402-9615
- Inheritance
- Autosomal dominant
- Source dataset
- Sniff Atlas v1.0.1 / DOI
Top 25 well-sampled breeds (n ≥ 50)
Maximum carrier frequency per breed across variants in the Donner 2023 cohort, with Wilson 95% confidence intervals. The list below is split into well-sampled breeds (n ≥ 50 tested) and small-sample breeds (n < 50, where the Wilson CI typically spans more than 20 percentage points and frequencies should not be compared directly to the well-sampled entries). Frequencies are population-level, not per-litter or per-line.
| Breed | Carrier frequency | n tested |
|---|---|---|
| Collie | 56.4% | 1,207 |
| Australian Shepherd | 24.3% | 2,296 |
| Miniature American Shepherd | 11.9% | 1,476 |
| Shetland Sheepdog | 11.1% | 945 |
| Old English Sheepdog | 5.3% | 423 |
| German Shepherd | 2.0% | 15,647 |
| Siberian Husky | 2.0% | 9,035 |
| Chow Chow | 2.0% | 643 |
| Border Collie | 2.0% | 6,712 |
| Norwegian Elkhound | 2.0% | 166 |
| Australian Cattle Dog | 2.0% | 982 |
| Lhasa Apso | 2.0% | 243 |
| Great Pyrenees | 2.0% | 1,985 |
| Alaskan Malamute | 2.0% | 504 |
| Boxer | 2.0% | 4,557 |
| Dobermann Pinscher | 2.0% | 2,219 |
| American Staffordshire Terrier | 2.0% | 42,789 |
| Poodle Miniature | 2.0% | 3,555 |
| Chihuahua | 2.0% | 4,273 |
| Beagle | 2.0% | 5,292 |
| Basset Hound | 2.0% | 990 |
| Labrador Retriever | 2.0% | 16,853 |
| Bulldog Standard | 2.0% | 4,816 |
| Golden Retriever | 2.0% | 12,880 |
| Pembroke Welsh Corgi | 2.0% | 4,371 |
Top 25 of 29 well-sampled breeds with at least one observed carrier shown.
▸ Also observed in 1 small-sample breed (n < 50)
Frequencies in this section are statistical estimates with wide Wilson 95% confidence intervals (typically >20 percentage points). Treat these as "carriers observed but the true population frequency is not yet measurable" rather than as comparable to the well-sampled entries above.
| Breed | Estimate | n tested |
|---|---|---|
| Lacy Dog | 2.0% | 32 |
236 additional breeds in the Donner 2023 cohort were tested but showed no carriers.
From genotype to phenotype
Carrier status is not the same as disease status. Penetrance is the fraction of at-risk dogs that develop the phenotype. The Donner 2023 S4 table tracks this for 1 variant(s) underlying this disease in the cohort.
- At-risk dogs evaluated
- 2
- Phenotype confirmed
- 1
- Penetrance range
- 50% to 50%
Predicted disease relevance at the per-dog level is UNPROVEN. Carrier frequency is measured; phenotype outcome is governed by penetrance, environment, and modifier loci. Consult a veterinarian for clinical interpretation.
Citations
If you use this record in published work, cite the Sniff Atlas (the published dataset that carries the breed-level carrier frequencies) and the upstream sources:
- Sniff Atlas v1.0.1 for the per-breed carrier frequencies:
Gehring, M. (2026). Sniff Atlas v1.0.1. Zenodo. https://doi.org/10.5281/zenodo.20566358. CC-BY 4.0.
- OMIA for the disease definition, inheritance, and gene assignment:
Nicholas, F. W., & Tammen, I. (2024). OMIA. Sydney Informatics Hub, The University of Sydney. https://doi.org/10.25910/2AMR-PV70. Entry: OMIA:001402-9615.
- Donner et al. 2023 for the breed × variant carrier-frequency cohort:
Donner, J., et al. (2023). PLOS Genetics, 19(3), e1010651. https://doi.org/10.1371/journal.pgen.1010651.
Full citation formats (BibTeX, RIS, CITATION.cff) at sniff.world/cite.
Related
- Sniff Atlas v1.0.1 — the source dataset for these frequencies.
- Browse breeds — per-breed Mendelian profiles, including this disease in context.
- OMIA entry OMIA:001402-9615 — authoritative clinical reference.