Great Pyrenees
Great Pyreneess have a cited life expectancy of 10.9 years (McMillan 2024 / VetCompass, n=260, 95% CI 10.5 to 11.3). The most carried tested variant is Canine Multifocal Retinopathy 1, in 12% of 1,985 Great Pyreneess tested (Donner 2023), then Pituitary-Dependent Hyperadrenocorticism (12%) and Degenerative Myelopathy (8.3%). 20 dogs stand behind the atlas figures here, so treat this page as an early sketch.
Also known as Chien De Montagne Des Pyrenees, Chien des Pyrenees, GP, and Montanes del Pirineo.
What genetic diseases do Great Pyreneess carry?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Great Pyreneess carry 23 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.
BEST1what this gene does
BEST1 is a gene that helps maintain the health of the retina, the light-sensitive layer at the back of the eye. It plays a role in keeping the cells in the retina functioning properly.
For your dog: If your dog is from a breed known to carry BEST1 variants, it’s worth discussing retinal health with your vet, especially if you notice any vision changes.
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.
NHEJ1what this gene does
NHEJ1 is a gene involved in repairing breaks in DNA, helping maintain the integrity of genetic information in cells.
For your dog: If your dog belongs to one of the breeds known to carry this gene variant, it's worth discussing testing with your vet to understand any potential eye health risks.
PRCDwhat this gene does
PRCD is a gene involved in the health of a dog's retina, the part of the eye that detects light and helps with vision.
For your dog: If your dog belongs to a breed known to carry PRCD changes, it's worth discussing eye health and potential genetic testing with your vet.
SLC2A9what this gene does
SLC2A9 is a gene that helps regulate uric acid levels in a dog's body. It plays a role in how the kidneys handle this substance.
For your dog: If your dog is one of the breeds known to carry this gene variant, it’s worth discussing with your vet to understand any potential urinary health concerns.
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.
ABCB1what this gene does
ABCB1 is a gene that helps control how certain drugs are processed and cleared from a dog's body.
For your dog: If your dog is from a breed that carries this gene variant, ask your vet about medication sensitivities before giving any new drugs.
SLC7A9what this gene does
SLC7A9 is a gene that helps transport certain amino acids in the kidneys. It plays a role in how the body handles cystine, an amino acid that can form crystals.
For your dog: If your dog is a carrier, it’s worth discussing with your vet to monitor urinary health and catch any issues early.
FGF4what this gene does
FGF4 influences leg length by affecting bone growth, leading to shorter legs in certain breeds.
For your dog: If your dog is from a breed known to carry this gene, it's worth discussing spinal health with your vet, but being a carrier doesn’t guarantee problems.
F7what this gene does
The F7 gene helps produce a protein important for blood clotting, which stops bleeding when dogs get injured.
For your dog: If your dog is from a breed known to carry F7 variants, it's worth mentioning to your vet before any surgery or if you notice unusual bleeding.
PNPLA1what this gene does
PNPLA1 is a gene involved in maintaining the skin's barrier by helping produce essential fats that keep the skin healthy and hydrated.
For your dog: If your dog is from a breed known to carry PNPLA1 variants and shows persistent dry, flaky skin, it's worth discussing with your vet to understand if genetics might be playing a role.
SLC3A1what this gene does
SLC3A1 is a gene that helps transport certain amino acids in the kidneys. It plays a key role in preventing the buildup of cystine, which can form stones.
For your dog: If your dog is from a breed known to carry SLC3A1 variants, it’s worth discussing cystinuria risks with your vet, especially if urinary issues arise.
ANO6what this gene does
ANO6 is a gene that helps regulate how blood cells expose certain signals on their surface, which is important for normal blood clotting.
For your dog: If your dog is from a breed known to carry ANO6 mutations, it’s worth discussing with your vet before any procedures to ensure bleeding risks are managed.
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.
ABCA4what this gene does
ABCA4 is a gene that helps manage the transport of molecules in the retina, the part of the eye responsible for vision.
For your dog: If your dog is from a breed known to carry ABCA4 variants, it's worth discussing eye health with your vet, especially as they age.
NDRG1what this gene does
NDRG1 is a gene involved in nerve cell function and maintenance, helping keep the nervous system working properly.
For your dog: If your dog is from a breed known to carry NDRG1 variants, it’s worth discussing with your vet, especially if you notice any mobility issues.
RBM20what this gene does
RBM20 is a gene that helps control how the heart muscle builds and repairs itself. It plays a key role in keeping the heart's pumping function strong.
For your dog: If you have a dog from these breeds, it’s worth discussing heart health with your vet, especially as your dog ages.
DNM1what this gene does
DNM1 is a gene that helps nerve cells communicate properly by managing how they send signals during muscle activity.
For your dog: If your dog belongs to one of the breeds known to carry this gene variant, it's worth discussing EIC with your vet, especially if your dog is very active or shows signs of weakness during exercise.
Show the other 3, ordered after these by severity, then carrier frequency.
What these results mean for a Great Pyrenees
8.3% of Great Pyreneess in the Donner 2023 cohort carried it (n=1,985).
- DM is a loss of function in the spinal cord that begins in adulthood and progresses to paralysis of the back legs. There is no treatment that stops it.
OMIA 000263-9615
“This is an adult onset degeneration of the spinal cord that progresses to paraplegia and tetraparesis. There is no successful treatment. A genetic test is available.” OMIA 000263-9615
- Two copies of the SOD1 variant mean at risk, not affected. Some dogs with two copies never show signs.
OMIA 000263-9615
“some homozygous mutant dogs had no signs of degenerative myelopathy, which suggests incomplete penetrance or other causative loci” OMIA 000263-9615
- One copy makes a dog a carrier. In the study that found the variant, every affected dog tested had two copies.
OMIA 000263-9615
“All affected dogs tested were homozygous mutant.” OMIA 000263-9615
What to do
A DNA result is not a diagnosis. Take the result, and any change in how the dog walks, to a veterinarian.
No test, or a mix
Without a test nobody can say how many copies a dog has. A breed's carrier frequency describes the breed, not this dog.
Other names
The Great Pyrenees is also recorded as Chien De Montagne Des Pyrenees, Chien des Pyrenees, GP, Montanes del Pirineo, Patou, Perro de Montana de los Pirineos, PMD, and Pyr.
Identified as Great Pyrenees (VBO:0200629) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 137 · iDog 120 · VeNom 14448.
For researchers Population genetics, disease models and every recorded condition Open the research detail for the Great Pyrenees
In the atlas, the Great Pyrenees clusters consistently as Great Pyrenees (100% of the 20 dogs here). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.
Only 20 dogs of this breed in the atlas, modestly sampled.
What the atlas genotypes say about Great Pyrenees
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.
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.
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.
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.
Great Pyreneess are a natural model for human disease
Because the same genes cause the same conditions across species, the inherited conditions documented in Great Pyreneess help researchers understand, and work toward treating, the human diseases they model. This is the dog advancing human medicine. The breed models the human disease; it does not have it, and this is not a prediction for your dog.
- amyotrophic lateral sclerosis type 1, modeled by the breed's Degenerative myelopathy via SOD1, the same underlying biology.
- Glanzmann thrombasthenia 1, modeled by the breed's Thrombasthenia via ITGA2B, the same underlying biology.
- Charlevoix-Saguenay spastic ataxia, modeled by the breed's Ataxia, spastic, SACS-related , the same underlying biology.
- congenital factor XI deficiency, modeled by the breed's Factor XI deficiency , the same underlying biology.
- autosomal recessive bestrophinopathy, modeled by the breed's Multifocal retinopathy 1 , the same underlying biology.
- OMIM:174500, modeled by the breed's Polydactyly , the same underlying biology.
Every condition recorded in the Great Pyrenees
Beyond the testable carriers above, OMIA's literature catalogue records 8 genetic conditions in the Great Pyrenees, 6 of which have a known human equivalent. This is the documented landscape across all Great Pyreneess ever studied, not a prediction for any one dog.
- Degenerative myelopathy Autosomal recessiveHuman equivalent: amyotrophic lateral sclerosis type 1
- Thrombasthenia AutosomalHuman equivalent: Glanzmann thrombasthenia 1
- Ataxia, spastic, SACS-related Autosomal recessiveHuman equivalent: Charlevoix-Saguenay spastic ataxia
- Factor XI deficiency AutosomalHuman equivalent: congenital factor XI deficiency
- Multifocal retinopathy 1 Autosomal recessiveHuman equivalent: autosomal recessive bestrophinopathy
- Polydactyly Autosomal dominantHuman equivalent: OMIM:174500
- Osteochondritis dissecans Multifactorial
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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Lived experience, kept beside the science.We have 20 great pyreneess. We do not have yours.
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- 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
- Brundage DM (2026). CanVAS: A Harmonized and Imputed Canine Variant Atlas. bioRxiv. doi:10.64898/2026.04.13.718238
- 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).