Xoloitzcuintli
Only 8 Xoloitzcuintlis have been tested for disease variants (Donner 2023), too few to say which variants the breed has. 20 dogs stand behind the atlas figures here, so treat this page as an early sketch.
Also known as Mexican Hairless Dog, Xolito, Xolo, and Xoloescuincle.
Which disease variants turn up in Xoloitzcuintlis?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), one turns up in Xoloitzcuintlis 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.
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.
What these results mean for a Xoloitzcuintli
A bladder-stone (cystinuria) test that doesn't hold up
Not a reliable testAbout 6 in every 100 copies of this gene in the 8 Xoloitzcuintlis tested carry this change (Donner 2023).
- Some DNA tests check this gene change for bladder stones. The researchers who studied it found it doesn't cause them, and they advise against using it as a test.
OMIA 001880-9615
“there appears to be no support for the variant to be causal” OMIA 001880-9615
“strongly recommend not to use "the variant in SLC7A9 as a test to predict the risk of developing cystinuria in male English bulldogs.” OMIA 001880-9615
What to do
A result for this change, either way, tells you nothing about bladder stones. If your dog strains to pee or there's blood in the urine, see a vet, whatever a DNA test said.
Not tested, or a mix
Nothing to do. There's no reason to test for this one.
Other names
The Xoloitzcuintli is also recorded as Mexican Hairless Dog, Xolito, Xolo, Xoloescuincle, Xoloitzcuintle, and Xoloitzquintle.
Identified as Xoloitzcuintli (VBO:0201436) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 234 · iDog 261 · VeNom 14434.
For researchers Population genetics, disease models and every recorded condition Open the research detail for the Xoloitzcuintli
In the atlas, the Xoloitzcuintli clusters consistently as Xoloitzcuintli (100% of the 20 dogs here). Genetic diversity is high (mean heterozygosity 0.3567), reflecting either a mixed-breed cluster or breeds with broad genetic backgrounds.
Mean heterozygosity is 0.357, notably high, which indicates a broad genetic background. Only 20 dogs of this breed in the atlas, modestly sampled.
What the atlas genotypes say about Xoloitzcuintli
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.
Xoloitzcuintlis are a natural model for human disease
Because the same genes cause the same conditions across species, the inherited conditions documented in Xoloitzcuintlis 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:120450, modeled by the breed's Comedo syndrome , the same underlying biology.
- OMIM:305100, modeled by the breed's Ectodermal dysplasia , the same underlying biology.
Every condition recorded in the Xoloitzcuintli
Beyond the testable carriers above, OMIA's literature catalogue records 2 genetic conditions in the Xoloitzcuintli, 2 of which have a known human equivalent. This is the documented landscape across all Xoloitzcuintlis ever studied, not a prediction for any one dog.
- Human equivalent: OMIM:120450
- Ectodermal dysplasia Autosomal incomplete dominantHuman equivalent: OMIM:305100
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 xoloitzcuintli never make it into a database. Add what you know as a Keeper, in your words →
Lived experience, kept beside the science.We have 22 xoloitzcuintlis. We do not have yours.
Every xoloitzcuintli 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).