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Brittany

Lifespan
11.1 years
95% CI 10.9 to 11.3 · McMillan 2024, n=991
Most carried variant
None at one percent or more among 349 tested (Donner 2023).
Behind this page
29 dogs
in the atlas · an early sketch · 349 tested for variants

Brittanys have a cited life expectancy of 11.1 years (McMillan 2024 / VetCompass, n=991, 95% CI 10.9 to 11.3). No tested variant is carried by one percent or more of the 349 Brittanys tested (Donner 2023). That describes the variants tested, not the breed's health. 29 dogs stand behind the atlas figures here, so treat this page as an early sketch.

Brittany
Photo: Wikimedia user Pharaoh Hound · CC BY-SA 3.0 · Wikimedia

Also known as Brittany Spaniel, Brittany Wiegref, Epagneul Breton, and French Brittany.

See in the atlas → From CanVAS
Mendelian-disease genetics

What genetic diseases do Brittanys carry?

From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Brittanys carry 4 of them at observable frequency. Carrier frequency is not clinical risk. Most recessive variants require two copies for disease expression; many dominant variants show incomplete penetrance. Read this as a population fingerprint of what's in the gene pool, not a per-dog prediction.

Dilated Cardiomyopathy risk factor (Discovered in the Doberman Pinscher; PDK4-related)
Autosomal dominant (Incomplete penetrance)
marker disputed 0.86%
n = 349 dogs · 2 variants tested · OMIA:000162-9615 · omia.org →
PDK4what this gene does

PDK4 helps regulate how cells use energy, especially in the heart muscle.

For your dog: If your dog is one of the breeds known to carry this gene, it’s worth discussing heart health with your vet, but being a carrier doesn’t mean your dog will develop disease.

Cone-Rod Dystrophy (cord1-PRA/crd4)
Autosomal recessive (Incomplete penetrance)
low 0.43%
n = 347 dogs · 1 variant tested · OMIA:001432-9615 · omia.org →
RPGRIP1what this gene does

RPGRIP1 is a gene involved in the function of photoreceptor cells in the eye, which help dogs see in different light conditions.

For your dog: If your dog belongs to a breed known to carry RPGRIP1 mutations, it’s worth discussing with your vet to understand the risks and monitor eye health.

Complement 3 (C3) Deficiency
Autosomal recessive
low 0.14%
n = 349 dogs · 1 variant tested · OMIA:000155-9615 · omia.org →
Degenerative Myelopathy (DM)
Autosomal recessive (Incomplete penetrance)
low 0.14%
n = 349 dogs · 1 variant tested · OMIA:000263-9615 · omia.org →
SOD1what this gene does

SOD1 is a gene that helps protect cells from damage caused by harmful molecules called free radicals.

For your dog: If your dog is a carrier of SOD1 variants, it's worth discussing with your vet, but remember carrier status doesn't mean your dog will get the disease.

Source: Donner J et al. 2023. Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2):e1010651 · Evidence: Limited (DTC ascertainment, tag-SNP proxy) · Confounding MEDIUM · License CC-BY-4.0 · Phene IDs from OMIA (Sydney School of Veterinary Science, The University of Sydney; DOI 10.25910/2AMR-PV70).
Sample size in this breed: 349 dogs from the Donner 2023 cohort.

Which Mendelian variants matter most for Brittanys?

The Mendelian-disease table above lists four variants screened in 349 Brittanys (Donner 2023). All four are rare in the breed. The carrier frequencies are low enough that routine screening is not a first-tier concern for most Brittany owners.

Cone-Rod Dystrophy (cord1-PRA/crd4)

Cone-Rod Dystrophy in Brittanys is an autosomal-recessive condition with incomplete penetrance. The disease causes progressive loss of sight, first in dim light, then in daylight. Carrier frequency is 0.43% (n=347). Not every carrier-by-carrier pairing produces affected puppies. Testing is available.

Complement 3 (C3) Deficiency

Complement 3 deficiency in Brittanys is an autosomal-recessive condition. The disease affects the immune system, and affected dogs struggle with certain infections. Carrier frequency is 0.14% (n=349). Testing is available through specialty labs.

How should I test my Brittany?

The four variants above are rare enough in Brittanys that a breed-specific panel is not cost-effective for most owners. If you are breeding, a single-gene test for whichever condition runs in your lines is the pragmatic choice. Ask your breed-club health contact or your vet which variant, if any, has appeared in your pedigree. If you are buying a puppy, ask the breeder whether they have tested parents for the four conditions listed above. Most Brittany breeders do not test because the variants are so infrequent.

What should I feed a Brittany?

Brittanys were built for all-day hunting across fields and marshes. A pet Brittany eating maintenance kibble in a house is being fed for a job they are not doing. Cited life expectancy for the breed is 11.1 years (McMillan 2024 / VetCompass, n=991; 95% CI 10.9 to 11.3), which is solid for a sporting breed; the priority in feeding is sustaining the lean, athletic build the breed standard expects and protecting the joints that carry that frame through field work.

Large-breed puppy formulations are unnecessary. Brittanys weigh 30 to 40 pounds at adulthood. A standard puppy formula with a calcium-to-phosphorus ratio between 1.1:1 and 2:1 (NRC 2006) is appropriate. The growth rate is not extreme; overfeeding puppy-formulated calories is a more common mistake than underfeeding.

Activity level is the real caloric lever. A Brittany working four days a week needs more food than a Brittany sleeping on the couch. The breed’s sporting heritage means the metabolism is responsive to work. If your Brittany is active, feed to maintain visible ribs with a one-finger indent of fat over the ribcage. If your Brittany is a house dog, reduce portions accordingly to prevent creeping weight gain. The breed is prone to becoming overweight when overfed, and excess weight accelerates joint wear.

Joint support matters because Brittanys are high-impact athletes. The carrier frequency for degenerative myelopathy is low (0.14%, Donner 2023, n=349), but the breed’s field-work intensity means hip and elbow stress is real. Omega-3 supplementation from fish oil (EPA + DHA) has evidence for joint support in high-activity dogs. The NRC 2006 standard does not mandate it; breed-club experience supports it for working Brittanys. An adult maintenance kibble with joint supplementation, or a high-quality fish oil added to the regular diet, is a reasonable choice for a hunting dog.

What we don’t know

The atlas cohort for Brittanys is small: 29 dogs. This is the honest limit of what the data can settle. The Donner 2023 screening (n=349) is larger and gives us solid carrier frequencies for the four detected variants, but 349 dogs is still a modest sample for a breed with thousands in the field.

We do not have Brittany-specific cancer prevalence data. The breed is not listed among the breeds with documented high cancer rates (like Goldens or Bernese Mountain Dogs), and no published cohort studies on Brittany mortality have been indexed. This does not mean cancer is not a concern; it means we have not systematically counted it in this breed.

Hip and elbow dysplasia are common in sporting breeds broadly. OFA does publish breed-specific hip and elbow statistics; check the OFA breed statistics page (ofa.org) for current Brittany figures. Ask your breeding prospect’s breeder for OFA or PennHIP scores on the parents; that is the actionable data point.

Frequently asked questions about Brittanys

Are Brittanys good for first-time dog owners? Brittanys are high-energy hunting dogs. They need daily exercise and do best with owners who understand the sporting-breed drive for activity and mental engagement. They are not good fits for sedentary households.

How long do Brittanys live? Cited life expectancy is 11.1 years (McMillan 2024 / VetCompass, n=991; 95% CI 10.9 to 11.3). Individual longevity varies with genetics, care, and lifestyle.

What is the most common health problem in Brittanys? The published data are sparse. Hip and elbow dysplasia are common in sporting breeds broadly, and joint wear from field work is the most frequent complaint among hunting Brittany owners. Ask your breeder for OFA scores on the parents.

Do Brittanys have genetic predispositions I should know about? Brittanys carry four documented Mendelian variants at low frequency (Donner 2023, n=349): a dilated cardiomyopathy risk factor (0.86%), cone-rod dystrophy (0.43%), degenerative myelopathy (0.14%), and C3 deficiency (0.14%). All are rare. Most Brittany owners will never encounter them.

Should I do a DNA test on my Brittany? If you are breeding, ask your breed-club health contact which variants, if any, run in your lines. If you are buying a puppy, ask the breeder whether parents have been tested. For pet owners, testing is not routine; the variants are too rare to justify screening cost.

What is the best diet for a Brittany? A grain-inclusive adult formula sized to maintain lean body condition is the standard. Activity level is the real dial: working Brittanys need more calories than house dogs. Omega-3 supplementation supports joints in high-activity dogs.

Are Brittanys prone to ear infections? Brittanys have pendant ears that can trap moisture, which is a general risk factor for otitis in dogs with drop ears. Regular ear cleaning after water exposure is routine preventive care. This is not genetic; it is breed anatomy.

Names & origins

Other names

The Brittany is also recorded as Brittany Spaniel, Brittany Wiegref, Epagneul Breton, and French Brittany.

Identified as Brittany (VBO:0200238) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs iDog 54 · VeNom 22569.

For researchers Population genetics, disease models and every recorded condition Open the research detail for the Brittany
What the atlas says about Brittany

In the atlas, the Brittany clusters consistently as Brittany (100% of the 29 dogs here). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.

Low breed predictability score (0.24), individual dogs of this breed vary widely in genetics, suggesting active substructure or sub-population diversity. Only 29 dogs of this breed in the atlas, modestly sampled.

Genetic dimensions · CanVAS atlas

What the atlas genotypes say about Brittany

Computed from the 14,478 CanVAS dogs in the Atlas, on an imputed genotype backbone: 77,215 directly typed sites per dog, imputed to 9.67 million variants.

The confidence below counts dogs, not reads: it is the size of the sample, and it is separate from how the genotypes were measured.

Dogs in the Atlas
29Founders
19 from Hayward2016, 10 from Spatola
Genetic diversity
0.32Moderate
Mean heterozygosity across the breed. 40th most diverse of 107 ranked populations.
What does genetic diversity mean?

How varied a breed's gene pool is — the share of gene spots where a typical dog of the breed carries two different versions rather than two identical ones.

How to read it: Higher = more diverse. Among well-sampled breeds it ranges roughly 0.22 (least diverse) to 0.33 (most diverse).

Diversity is a strength, not a verdict on any individual dog. Lower diversity means it's worth paying attention to recessive-risk testing — not that a dog is doomed.

Cluster structure
Single tight cluster
Intra-breed RMS distance: 35.06
What does within-breed variation mean?

How much individual dogs within the breed differ from each other genetically.

How to read it: Higher = more internal variety among individuals of the breed.

Sensitive to how many dogs of the breed we've sampled.

Related breeds
Built from
Close cousins
In the Sporting group
Explore the full lineage map →
VBO foundation stock (breeding records) · AKC breed group
Relatedness is documented lineage + kennel family. Genetic-ancestry distance measures diversity, not kinship, so it isn't used here.
How long they live
11.1years (life expectancy)
95% CI 10.9–11.3 · VetCompass, McMillan 2024, n=991. source
What does typical lifespan mean?

The median age dogs of the breed tend to reach.

How to read it: Higher = longer-lived. Compare to longevity-for-size to see whether it's just a size effect.

Drawn from population lifespan records; individual dogs vary widely with care, genetics, and luck.

n = 29 dogs · moderate sample · CanVAS (Brundage 2026) · Sniff Atlas
The data behind this page

Where every number on this page came from.

This page draws on three primary data sources. Carrier frequencies for the Mendelian section come from Donner et al. 2023 (CC-BY-4.0). We grade these data at evidence Limited because the cohort is a direct-to-consumer ascertainment, which biases toward owners who chose to test their dogs. The panel also uses tag-SNP proxies for some variants rather than direct causal-variant assays. Limited is a study-design grade, not a quality grade: the Donner cohort is the largest open canine-genotype dataset in existence and we are grateful for it. We rate the confounding MEDIUM.

Population-genetic dimensions (heterozygosity, intra-breed PCA distance, nearest neighbors, trait-locus frequencies) come from CanVAS (Brundage 2026), harmonized through the Sniff Atlas. The exact release date and verification commit are pinned at the bottom of the page so a researcher can trace a number back to a specific snapshot. The disease-gene-variant graph comes from OMIA (Online Mendelian Inheritance in Animals; Nicholas, Tammen, and the Sydney Informatics Hub at the Sydney School of Veterinary Science, The University of Sydney; retrieved April 2026, DOI 10.25910/2AMR-PV70).

What this page does not yet have. Inheritance modes and per-disease penetrance evidence from Donner 2023 are in the structured data for every variant the panel covers. Mondo, OMIM, Ensembl, and HGNC cross-references live on the gene and disease pages this page links to, rather than being repeated here. What is still absent from this breed page is anything not in the cited panel, and each such gap carries its cause where it appears.

How to cite this page. The computed dimensions on this page are derived from the open Sniff Atlas v1.0.1 (Gehring 2026, doi:10.5281/zenodo.20566358, CC-BY 4.0). Full citation formats including BibTeX, RIS, and CITATION.cff at sniff.world/cite.

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References
  1. Donner J, Freyer J, Davison S, Anderson H, Blades M, Honkanen L, et al. (2023). Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2):e1010651. doi:10.1371/journal.pgen.1010651
  2. Brundage DM (2026). CanVAS: A Harmonized and Imputed Canine Variant Atlas. bioRxiv. doi:10.64898/2026.04.13.718238
  3. Nicholas, F.W., Tammen, I., & Sydney Informatics Hub. (2026). Online Mendelian Inheritance in Animals (OMIA) [dataset]. The University of Sydney. https://omia.org. doi:10.25910/2AMR-PV70 (retrieved April 2026).
Last updated
Sources: CanVAS (Brundage 2026) · Donner 2023 · OMIA