Cystinuria Type I-B (SLC7A9 p.A217T)
Cystinuria Type I-B (SLC7A9 p.A217T). Autosomal recessive (incomplete penetrance). Observed in 64 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,662 dogs (Donner 2023). Per-dog phenotype outcome depends on penetrance, modifiers, and environment; the carrier frequencies below describe variant prevalence, not disease incidence.
- OMIA identifier
- OMIA:001880-9615
- InheritanceInheritance patternWhat it isHow the condition is passed down: recessive (two copies needed), dominant (one copy), or more complex.For your dogRecessive means a single-copy carrier is usually healthy but can still pass it on.PreciselyThe documented mode of Mendelian transmission (autosomal recessive or dominant, X-linked, etc.) per OMIA.OMIA · documented
- Autosomal recessive (incomplete penetrance)
- Linked gene
- SLC7A9
- Human counterpart
- In humans, this gene is SLC7A9. OMIM 604144
- Source dataset
- Sniff Atlas v1.0.1 / DOI
A model of human cystinuria
Dogs with this condition carry a change in SLC7A9. In people, changes in the same gene cause cystinuria. That makes affected dogs a naturally-occurring model of the human disease, and it is part of why studying dogs moves medicine forward for everyone. It does not mean your dog has the human disease. It means the two share an underlying biology.
In people, the disease is described as: Cystinuria is a renal tubular amino acid transport disorder characterized by recurrent formation of kidneys cystine stones.
In humans it is also called: CSNU, cystinuria (disease), cystinuria, type non-I, cystinuria-lysinuria, cystinuria-lysinuria syndrome.
Mapped from OMIA via the human disease's OMIM entry to the Mondo Disease Ontology (Monarch Initiative, CC-BY 4.0). Sniff renders this as a model-of link; the canine disease remains the subject of this page.
From OMIA's curated record
Documented in OMIA (Online Mendelian Inheritance in Animals). This describes the disease as recorded in the published literature, not a prediction for any individual dog. As of 2026-06-03.
Summary
Clinical features
Molecular genetics
A SLC7A9 variant (c.649A>G; p.(A217T) has been identified by Harnevik et al. (2006) in English bulldogs, but there appears to be no support for the variant to be causal (Harnevik et al., 2006; Ruggerone et al., 2016; Fitzwilliams et al. 2023). It appears that all affected English bulldogs in these three studies were also homozygous for two likely causal SLC3A1 variants (p.(I192V) and p.(S698G) (see OMIA:000256-9615 : Cystinuria, type I - A in Canis lupus familiaris). The affected dogs were reported to be also either heterozygous or homozygous for the SLC7A9 variant (Harnevik et al., 2006; Ruggerone et al., 2016, Fitzwilliams et al. 2023), which according to Fitzwilliams et al. (2023) is a common allele in the breed (allele frequency for c.649A is 0.52 in English bulldogs from Denmark). The data presented by Fitzwilliams et al. (2023) showed that 10 out of 14 non cystinuric male dogs were heterozygous or homozygous for the A allele. Fitzwilliams et al. (2023) strongly recommend not to use "the variant in SLC7A9 as a test to predict the risk of developing cystinuria in male English bulldogs.”
Inheritance
Human analog
OMIA links this condition to its human counterpart in OMIM (Mendelian Inheritance in Man), the place to read across to the deeper human literature for the same biology.
Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:001880-9615, doi:10.25910/2AMR-PV70 (CC-BY 4.0).
Published references
The peer-reviewed papers behind this disease, curated by OMIA. Starred entries are OMIA-designated landmark papers. Showing 6 of 7.
- Epidemiological evaluation of neuter status, sex, and breed in dogs with cystine uroliths. · J Vet Intern Med · 2025 · PMID 40298126
- Evaluation of the value of genetic testing for cystinuria in the Danish population of English bulldogs. · Anim Genet · 2023 · PMID 36971195
- Cystinuria in dogs and cats: What do we know after almost 200 years? · Animals (Basel) · 2021 · PMID 34438894
- Genetic evaluation of English bulldogs with cystine uroliths. · Vet Rec · 2016 · PMID 27388977
- Urolithiasis. · Vet Clin North Am Small Anim Pract · 2015 · PMID 26002797
- SLC3A1 and SLC7A9 mutations in autosomal recessive or dominant canine cystinuria: a new classification system. · J Vet Intern Med · 2013 · PMID 24001348
References curated by OMIA (Nicholas, Tammen & the Sydney Informatics Hub), doi:10.25910/2AMR-PV70 (CC-BY 4.0). Full list at the OMIA entry.
Set each parent's status for Cystinuria Type I-B (SLC7A9 p.A217T) and see the odds for their puppies. Single recessive variant, exact Mendelian math.
These are the genetic odds for one known variant, not a promise: a real litter varies around them, and penetrance or other genes can change whether the condition ever appears. Use it to avoid pairing two carriers and to keep a line healthy, not to engineer a dog. Inheritance mode per OMIA.
See what Cystinuria Type I-B (SLC7A9 p.A217T) looks like in your dog's breed.
Top 25 well-sampled breeds (n ≥ 50)
Maximum carrier frequencyCarrier frequencyWhat it isHow many dogs in a breed carry one copy of a disease variant, usually without being affected themselves.For your dogA carrier is typically healthy. For most recessive conditions a dog needs two copies to be at risk.PreciselyThe proportion of a population carrying at least one copy of the variant allele. Population prevalence, not disease incidence.Sniff Atlas (Donner 2023) · measured per breed across variants in the Donner 2023 cohort, with Wilson 95% confidence intervalsWilson 95% confidence intervalWhat it isThe range the true frequency is probably in. A wide range means we are less sure, usually because few dogs were tested.For your dogTrust tight ranges; treat wide ones as rough estimates.PreciselyA binomial-proportion confidence interval (Wilson score, 95%) that stays reliable at small sample sizes.Sniff Atlas methodology · statistical. The list below is split into well-sampled breeds (n ≥ 50 tested) and small-sample breeds (n < 50, where the Wilson CI typically spans more than 20 percentage points and frequencies should not be compared directly to the well-sampled entries). Frequencies are population-level, not per-litter or per-line.
▸ Full table with Wilson 95% confidence intervals
| Breed | Carrier frequency | n tested |
|---|---|---|
| Bulldog Standard | 55.5% | 4,816 |
| Swedish Vallhund | 25.6% | 88 |
| Golden Retriever | 23.7% | 12,881 |
| Bull Terrier Standard | 22.7% | 468 |
| Bulldog American | 15.0% | 540 |
| English Cocker Spaniel | 12.2% | 580 |
| Boerboel | 11.2% | 165 |
| Parson Russell Terrier | 8.6% | 181 |
| Catahoula Leopard Dog | 6.8% | 154 |
| Soft Coated Wheaten Terrier | 6.8% | 607 |
| Dalmatian | 6.4% | 820 |
| Maltese | 5.3% | 2,413 |
| English Springer Spaniel | 4.4% | 751 |
| Great Dane | 4.2% | 3,266 |
| Bernese Mountain Dog | 4.0% | 955 |
| Mastiff | 3.3% | 767 |
| American Staffordshire Terrier | 2.9% | 42,793 |
| Cairn Terrier | 1.9% | 183 |
| Blue Tick Coonhound | 1.4% | 104 |
| Border Terrier | 1.4% | 71 |
| Saint Bernard | 0.97% | 721 |
| Chinese Shar Pei | 0.88% | 400 |
| Schnauzer Giant | 0.87% | 230 |
| Russell Terrier | 0.84% | 239 |
| Danish Swedish Farmdog | 0.82% | 61 |
Top 25 of 55 well-sampled breeds with at least one observed carrier shown.
▸ Also observed in 9 small-sample breeds (n < 50)
Frequencies in this section are statistical estimates with wide Wilson 95% confidence intervals (typically >20 percentage points). Treat these as "carriers observed but the true population frequency is not yet measurable" rather than as comparable to the well-sampled entries above.
| Breed | Estimate | n tested |
|---|---|---|
| Bedlington Terrier | 40.9% | 11 |
| Kuvasz | 28.6% | 7 |
| Polish Tatra Sheepdog | 25.0% | 8 |
| Briard | 10.7% | 14 |
| German Pinscher | 10.0% | 30 |
| Xoloitzcuintli | 6.3% | 8 |
| Black Russian Terrier | 4.3% | 23 |
| Lacy Dog | 1.6% | 32 |
| Mudi | 1.2% | 42 |
202 additional breeds in the Donner 2023 cohort were tested but showed no carriers.
Scope
This record carries the breed-level carrier frequencies from the Donner 2023 cohort. Penetrance data (the fraction of at-risk dogs that develop the phenotype) is not yet quantified for this disease in the Sniff Atlas v1.0.1. The OMIA entry is the authoritative reference for the clinical phenotype, inheritance pattern, and gene assignment.
Predicted disease relevance at the per-dog level is UNPROVEN. The carrier frequency is measured; phenotype outcome depends on penetrance, environment, and modifier loci. Consult a veterinarian for clinical interpretation.
Citations
If you use this record in published work, cite the Sniff Atlas (the published dataset that carries the breed-level carrier frequencies) and the upstream sources:
- Sniff Atlas v1.0.1 for the per-breed carrier frequencies:
Gehring, M. (2026). Sniff Atlas v1.0.1. Zenodo. https://doi.org/10.5281/zenodo.20566358. CC-BY 4.0.
- OMIA for the disease definition, inheritance, and gene assignment:
Nicholas, F. W., & Tammen, I. (2024). OMIA. Sydney Informatics Hub, The University of Sydney. https://doi.org/10.25910/2AMR-PV70. Entry: OMIA:001880-9615.
- Donner et al. 2023 for the breed × variant carrier-frequency cohort:
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. https://doi.org/10.1371/journal.pgen.1010651.
Full citation formats (BibTeX, RIS, CITATION.cff) at sniff.world/cite.
Related
- Sniff Atlas v1.0.1, the source dataset for these frequencies.
- Browse breeds, per-breed Mendelian profiles, including this disease in context.
- OMIA entry OMIA:001880-9615, authoritative clinical reference.
- About OMIA, the catalogue this record comes from, and how Sniff uses it.