Tibetan Mastiff
The tested variant with the highest allele frequency is Cystinuria Type I-A, at 3.1% among the 32 Tibetan Mastiffs tested (Donner 2023; gene copies, not dogs). 35 dogs stand behind the atlas figures here, so treat this page as an early sketch.
Also known as Do-Khyi.
Which disease variants turn up in Tibetan Mastiffs?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), 2 turn up in Tibetan Mastiffs at observable frequency. The figure beside each is its allele frequency. Of the gene copies tested in this breed, the share that carry the variant. Every dog carries two copies, so this is not the share of dogs. It 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.
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.
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.
What these results mean for a Tibetan Mastiff
A heart (DCM) test that doesn't hold up
Not a reliable testAbout 6 in every 100 copies of this gene in the 32 Tibetan Mastiffs tested carry this change (Donner 2023).
- This gene change was linked to a heart disease called DCM in Dobermans, but it hasn't been shown to cause it. The curated record says a test for it isn't a good guide to heart risk, even in Dobermans.
OMIA 000162-9615
“it is evident that any DNA test based on this marker will not be a good indicator of liability to this disorder in Dobermans” OMIA 000162-9615
What to do
A result for this one isn't, by itself, a reason for heart tests. Whether to check your dog's heart is a conversation to have with your vet.
Not tested, or a mix
Outside the Doberman, no one has shown what this change means.
About 3 in every 100 copies of this gene in the 32 Tibetan Mastiffs tested carry this change (Donner 2023).
- The kidneys can't hold on to cystine, one of the building blocks of protein. It can form crystals and stones that block the flow of urine.
OMIA 000256-9615
“Cystinuria, type 1 - A is an inherited defect that causes failure of reabsorption of cystine in the proximal renal tubule, leading to cystine precipitation in the urine. Formation of crystals and calculi lead to urolithiasis and urinary tract obstruction.” OMIA 000256-9615
What to do
If your dog is straining to pee, or passing little or none, see a vet the same day.
Not tested, or a mix
Without a test, no one can tell how many copies your dog has.
Other names
The Tibetan Mastiff is also recorded as Do-Khyi.
Identified as Tibetan Mastiff (VBO:0201351) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 230 · iDog 242 · VeNom 14432.
For researchers Population genetics, disease models and every recorded condition Open the research detail for the Tibetan Mastiff
In the atlas, the Tibetan Mastiff clusters consistently as Tibetan Mastiff (100% of the 35 dogs here). Genetic diversity is high (mean heterozygosity 0.3502), reflecting either a mixed-breed cluster or breeds with broad genetic backgrounds.
Mean heterozygosity is 0.350, notably high, which indicates a broad genetic background.
What the atlas genotypes say about Tibetan Mastiff
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.
Tibetan Mastiffs are a natural model for human disease
Because the same genes cause the same conditions across species, the inherited conditions documented in Tibetan Mastiffs 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.
- Griscelli syndrome type 3, modeled by the breed's Coat colour, dilution, MLPH-related , the same underlying biology.
Every condition recorded in the Tibetan Mastiff
Beyond the testable carriers above, OMIA's literature catalogue records 3 genetic conditions in the Tibetan Mastiff, 1 of which have a known human equivalent. This is the documented landscape across all Tibetan Mastiffs ever studied, not a prediction for any one dog.
- Coat colour, dilution, MLPH-related Autosomal recessiveHuman equivalent: Griscelli syndrome type 3
- Osteochondritis dissecans Multifactorial
Where every number on this page came from.
This page draws on three primary data sources. Allele 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 v1.0.2 (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 tibetan mastiff never make it into a database. Add what you know as a Keeper, in your words →
Lived experience, kept beside the science.We have 36 tibetan mastiffs. We do not have yours.
Every tibetan mastiff 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).