Leonberger
Leonbergers have a cited life expectancy of 10 years (McMillan 2024 / VetCompass, n=676, 95% CI 9.5 to 10.3). No tested variant is carried by one percent or more of the 21 Leonbergers tested (Donner 2023). That describes the variants tested, not the breed's health. 25 dogs stand behind the atlas figures here, so treat this page as an early sketch.
Also known as Gentle Giant, Gentle Lion, and Leo.
Other names
The Leonberger is also recorded as Gentle Giant, Gentle Lion, and Leo.
Identified as Leonberger (VBO:0200819) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 145 · iDog 152 · VeNom 14361.
For researchers Population genetics, disease models and every recorded condition Open the research detail for the Leonberger
In the atlas, the Leonberger clusters consistently as Leonberger (100% of the 25 dogs here). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.
Only 25 dogs of this breed in the atlas, modestly sampled.
Median lifespan is 10.0 years, slightly shorter than expected for the breed size (59.25 kg).
What the atlas genotypes say about Leonberger
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.
Leonbergers are a natural model for human cancer.
Some cancers appear in Leonbergers and in people driven by the same somatically-altered genes, cohort by cohort and cited on both sides. That makes this breed part of how we understand, and one day treat, the human disease. This is not a prediction about your dog, it is a window into the biology we share.
Leonbergers are a natural model for human disease
Because the same genes cause the same conditions across species, the inherited conditions documented in Leonbergers 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.
- OMIM:203290, modeled by the breed's Coat colour, brown, TYRP1-related via TYRP1, the same underlying biology.
- OMIM:618186, modeled by the breed's Laryngeal paralysis and polyneuropathy, CNTNAP1-related , the same underlying biology.
- OMIM:612334, modeled by the breed's Leukoencephalomyelopathy, NAPEPLD-related , the same underlying biology.
- OMIM:269200, modeled by the breed's Polyglandular autoimmune syndrome, type II , the same underlying biology.
- OMIM:608236, modeled by the breed's Polyneuropathy, ARHGEF10-related , the same underlying biology.
- OMIM:601455, modeled by the breed's Polyneuropathy, generic , the same underlying biology.
Every condition recorded in the Leonberger
Beyond the testable carriers above, OMIA's literature catalogue records 10 genetic conditions in the Leonberger, 9 of which have a known human equivalent. This is the documented landscape across all Leonbergers ever studied, not a prediction for any one dog.
- Coat colour, brown, TYRP1-related Autosomal recessiveHuman equivalent: OMIM:203290
- Laryngeal paralysis and polyneuropathy, CNTNAP1-related Autosomal recessiveHuman equivalent: OMIM:618186
- Leukoencephalomyelopathy, NAPEPLD-related Autosomal recessiveHuman equivalent: OMIM:612334
- Human equivalent: OMIM:269200
- Polyneuropathy, ARHGEF10-related Probably autosomal recessiveHuman equivalent: OMIM:608236
- Polyneuropathy, generic Autosomal recessiveHuman equivalent: OMIM:601455
- Polyneuropathy, GJA9-related Autosomal incomplete dominantHuman equivalent: OMIM:611923
- Human equivalent: OMIM:248250
- Human equivalent: OMIM:618329
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.
Some things about living with a leonberger never make it into a database. Add what you know as a Keeper, in your words →
Lived experience, kept beside the science.We have 25 leonbergers. We do not have yours.
Every leonberger added sharpens the breed's genetic neighborhood. Enrollment is free. The data stays open. The star is permanent.
- 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).