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Canine Mendelian disease record

Cerebellar Cortical Degeneration (Discovered in the Vizsla; CCD)

Cerebellar Cortical Degeneration (Discovered in the Vizsla; CCD). Autosomal recessive. Observed in 0 of 266 breeds tested in the Sniff Atlas, with measured variant frequencies drawn from 242,664 dogs (Donner 2023). Whether a dog carrying this variant is at risk depends on the disease’s inheritance pattern; outcome also depends on penetrance, modifiers, and environment. The frequencies below describe variant prevalence, not confirmed disease incidence.

OMIA identifier
OMIA:002034-9615
Autosomal recessive
Linked gene
SNX14
Human counterpart
In humans, this gene is SNX14. OMIM 616105 In people, SNX14 appears tolerant of loss-of-function variation (gnomAD v4.1 constraint, LOEUF 0.85). Constraint measures intolerance to loss-of-function only and does not indicate importance; some tolerant genes cause disease through other mechanisms. In people, variants in the SNX14 gene have conflicting classifications in ClinVar, and none is expert-reviewed. The evidence is unsettled, not that variants here are benign.
Source dataset
Sniff Atlas v1.0.1 / DOI
The human connection

A model of human autosomal recessive spinocerebellar ataxia 20

Dogs with this condition carry a change in SNX14. In people, changes in the same gene cause autosomal recessive spinocerebellar ataxia 20. 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: Any autosomal recessive cerebellar ataxia in which the cause of the disease is a mutation in the SNX14 gene.

In humans it is also called: SCAR20, SNX14 autosomal recessive cerebellar ataxia, spinocerebellar ataxia, autosomal recessive 20.

MONDO:0014601 OMIM 616354

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.

About this disease

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

Ataxia is characterized by uncoordinated movements and represents a relatively non-specific clinical sign. This entry describes an ataxia form that is caused by a genetic variant in the SNX14 gene. Phenotypically related ataxias in dogs may also be caused by variants in more than 30 other genes (Cocostîrc et al. 2023; Stee et al. 2023). Thus, locus heterogeneity for this phenotype must be considered.

Clinical features

Fenn et al. (2016) report two affected littermates "with a history of progressive ataxia, starting around three months of age. Clinical signs included marked hypermetric and dysmetric ataxia, truncal sway, intention tremors and absent menace responses, with positional horizontal nystagmus in one dog. Routine diagnostic investigations were unremarkable, and magnetic resonance imaging performed in one dog revealed mild craniodorsal cerebellar sulci widening, supportive of cerebellar atrophy."

Molecular genetics

Fenn et al. (2016): "an exon 26 splice donor variant (CanFam3.1, chr12:45,530,566, c.2653 + 1G > A) in the Sorting Nexin 14 (SNX14) gene"

Pathology

Fenn et al. (2016): "Owners of both dogs elected for euthanasia shortly after the onset of signs. Histopathological examination revealed primary Purkinje neuron loss consistent with CCD [cerebellar cortical degeneration]."

Prevalence

Fenn et al. (2016): "Genetic screening of 133 unaffected Hungarian Vizslas revealed the presence of three heterozygotes, supporting the presence of carriers in the wider population"

History

Fenn et al. (2016) were the first to report the occurrence of this disorder in the Hungarian Vizsla breed.

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.

Disease · OMIM 616354 Gene · OMIM 616105

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:002034-9615, doi:10.25910/2AMR-PV70 (CC-BY 4.0).

The evidence

Published references

The peer-reviewed papers behind this disease, curated by OMIA. Starred entries are OMIA-designated landmark papers.

  1. Phenotypic and genetic aspects of hereditary ataxia in dogs. · J Vet Intern Med · 2023 · PMID 37341581

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.

Your breed

See what Cerebellar Cortical Degeneration (Discovered in the Vizsla; CCD) looks like in your dog's breed.
Variant frequency by breed

Observed only in small-sample breeds

Maximum variant frequency per breed across variants in the Donner 2023 cohort, with . 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.

Scope of this record

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 variant frequency is measured; phenotype outcome depends on penetrance, environment, and modifier loci. Consult a veterinarian for clinical interpretation.

How to cite this record

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:002034-9615.

  • 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

Related

Last updated
Sources: Sniff Atlas v1.0.1 · OMIA OMIA:002034-9615 · Donner et al. 2023 · gnomAD v4.1 (Karczewski 2020) · ClinVar (Landrum 2018)