Skip to main content
snıff
Canine Mendelian disease record

Spinocerebellar Ataxia (Late-Onset Ataxia; CAPN1-related; SCA/LOA)

Spinocerebellar Ataxia (Late-Onset Ataxia; CAPN1-related; SCA/LOA). Autosomal recessive. Observed in 1 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,664 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:001820-9615
Autosomal recessive
Source dataset
Sniff Atlas v1.0.1 / DOI
The human connection

A model of human autosomal recessive spastic paraplegia type 76

This is the canine counterpart of autosomal recessive spastic paraplegia type 76 in people. 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: Autosomal recessive spastic paraplegia type 76 is a rare, complex hereditary spastic paraplegia characterized by adult onset slowly progressive, mild to moderate lower limb spasticity and hyperreflexia, resulting in gait disturbances, commonly associated with upper limb hyperreflexia and dysarthria. Foot deformities (usually pes cavus) and extensor plantar responses are also frequent. Additional features may include ataxia, lower limb weakness/amyotrophy, abnormal bladder function, distal sensory loss and mild intellectual deterioration.

In humans it is also called: SPG76, hereditary spastic paraplegia type 76, spastic paraplegia 76, autosomal recessive.

MONDO:0014827 OMIM 616907

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 CAPN1 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

The clinics and pathology of "hereditary ataxia" in Jack Russell and Parson Russell Terriers were mostly studied before the different causative variants in CAPN1 (this entry) and KCNJ10 (see the related entry 002089-9615) were identified. It is therefore not fully clear which genetic form of ataxia was investigated in the earlier publications. It is likely that there are even more genetically distinct forms of ataxia present in Russell group terriers. The CAPN1 form of this disease manifests as a slowly progressing pelvic limb incoordination, with an onset usually at 2 to 9 months of age. As the disease progresses a characteristic “dancing” or “prancing” gait is displayed, especially affecting the pelvic limbs. The age at onset of Parson Russell Terrier cases that were used to identify the CAPN1:p.Cys115Tyr variant ranged between 7-12 months. (Forman et al. 2013). The supplementary video S1 in this publication illustrates the clinical phenotype.

Molecular genetics

Target-enriched deep sequencing of the 1.8Mb candidate region (see Mapping section) and checking identified mutations in various samples of dogs eventually enabled Forman et al. (2013) to claim "a missense mutation ([c.344G>A;] p.Cys115Tyr) in the gene encoding the large subunit of calcium dependent cysteine protease, μ-calpain (CAPN1)" as "a provocative candidate for the cause of SCA in the PRT [Parson Russell Terrier] and a novel potential cause of ataxia in humans."

History

It is important to note that the discovery of a likely causal variant for this disorder in dogs (documented below) by Forman et al. (2013) led to the discovery of likely causal variants for the homologous disorder in humans, Danio rerio (zebrafish), Drosophila melanogaster and Caenorhabditis elegans by Gan-Or et al. (2016), and in humans and mice by Wang et al. (2016).

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 616907 Gene · OMIM 114220

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:001820-9615, doi:10.25910/2AMR-PV70 (CC-BY 4.0).

Signs & cross-references

How it presents

Catalogued in the Mondo disease ontology (the cross-species disease identity used by the Monarch Initiative) as autosomal recessive spastic paraplegia type 76 (MONDO:0014827).

Phenotype terms: Human Phenotype Ontology + Mammalian Phenotype Ontology; disease terms: Mondo (Monarch Initiative). Cross-references curated by OMIA (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. Showing 6 of 16.

  2. Phenotypic and genetic aspects of hereditary ataxia in dogs. · J Vet Intern Med · 2023 · PMID 37341581
  6. [Correction to] Mutations in CAPN1 cause autosomal-recessive hereditary spastic paraplegia. · American Journal of Human Genetics · 2016 · PMID 27259058

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.

Predict a litter

Set each parent's status for Spinocerebellar Ataxia (Late-Onset Ataxia; CAPN1-related; SCA/LOA) and see the odds for their puppies. Single recessive variant, exact Mendelian math.

Parent A
Parent B
NNClear
NmCarrier
NmCarrier
mmAffected
Clear25%
Carrier50%
Affected25%

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.
Your breed

See what Spinocerebellar Ataxia (Late-Onset Ataxia; CAPN1-related; SCA/LOA) looks like in your dog's breed.
Carrier frequency by breed

Top 1 well-sampled breeds (n ≥ 50)

Maximum 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.

0%10%20%
Parson Russell Terrier6.4% · n 181
n = 181 dogs · Donner et al. 2023 carrier-screening cohort · Sniff Atlas
Each bar is one well-sampled breed; the whisker is its Wilson 95% CI, and fainter bars have wider intervals. Frequencies are population-level, not per-litter. Carrier status for Spinocerebellar Ataxia (Late-Onset Ataxia; CAPN1-related; SCA/LOA) is measured; phenotype outcome depends on penetrance and modifiers.
▸ Full table with Wilson 95% confidence intervals
Breed Carrier frequency n tested
Parson Russell Terrier 6.4% 181

265 additional breeds in the Donner 2023 cohort were tested but showed no carriers.

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 carrier 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:001820-9615.

  • 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:001820-9615 · Donner et al. 2023