How is Degenerative Myelopathy (DM) inherited in dogs?

Degenerative Myelopathy (DM) follows a Autosomal recessive (incomplete penetrance) inheritance pattern. It has been observed in 138 of 266 breeds screened in the Sniff Atlas.

What is the human equivalent of Degenerative Myelopathy (DM)?

OMIA links Degenerative Myelopathy (DM) to its human counterpart in OMIM (OMIM 105400, OMIM 618598), the bridge to the deeper human-medicine literature for the same underlying biology.

How well studied is Degenerative Myelopathy (DM) in dogs?

OMIA curates 69 peer-reviewed references for Degenerative Myelopathy (DM). The full, linked citation list is on this page.

Canine Mendelian disease record

Degenerative Myelopathy (DM)

Degenerative Myelopathy (DM). Autosomal recessive (incomplete penetrance). Observed in 138 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,641 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:000263-9615
Inheritance: Autosomal recessive (incomplete penetrance)
Source dataset: Sniff Atlas v1.0.1 / DOI

The human connection

A model of human amyotrophic lateral sclerosis type 1

Dogs with this condition carry a change in SOD1. In people, changes in the same gene cause amyotrophic lateral sclerosis type 1. 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 humans it is also called: ALS1, FALS, amyotrophic lateral sclerosis 1, amyotrophic lateral sclerosis 1, familial, amyotrophic lateral sclerosis, familial.

MONDO:0007103 OMIM 105400 OMIM 618598

Mapped from OMIA via the human disease's OMIM entry to the Mondo Disease Ontology (Monarch Initiative, CC-BY 4.0). Closely related human conditions exist for this gene. 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

This is an adult onset degeneration of the spinal cord that progresses to paraplegia and tetraparesis. There is no successful treatment. A genetic test is available. A different mutation in the SOD1 gene causes an early onset disease: OMIA:002322-9615 : Dyskinesia, paroxysmal, SOD1-related in Canis lupus familiaris.

Clinical features

Most dogs are at least 8 years of age at the onset of clinical signs, which include hyporeflexia, upper motor neuron proprioceptive spasticity and ataxia in the pelvic limbs. Widespread limb muscle atrophy can be observed and the disease progresses to paraplegia and eventually flaccid tetraparesis (Awano et al., 2009). Hyperesthesia, cranial nerve signs (e.g. difficulty in swallowing and barking), urinary and fecal incontinence (Coates et al., 2010) can be observed and in final stages of the disease respiratory muscles fail (Nardone et al., 2016). There is no effective treatment. [IT thanks DVM student Jane Lai for contributions to this entry in April 2022].

Molecular genetics

The first likely causative variant described is a G to A transition (c.118G>A; p.E40K) in exon 2 of SOD1. All affected dogs tested were homozygous mutant. However, some homozygous mutant dogs had no signs of degenerative myelopathy, which suggests incomplete penetrance or other causative loci (Awano et al., 2009). The mutation is hypothesized to lead to SOD1 aggregation, as cytoplasmic inclusions in affected dogs stain with anti-SOD1 antibodies (Awano et al., 2009). A second causal mutation (c.52A>T; p.Thr18Ser) in the same gene, in a Bernese Mountain Dog, was reported by Wininger et al. (2011). Having genotyped 408 Bernese Mountains dogs for both the above mutations, Pfahler et al. (2014) reported that "The c.118G>A mutation was heterozygous in 188 (46.1%) and homozygous in 27 (6.6%) BMD (Table S2). The c.52A>T mutation was heterozygous in 65 (15.9%) and homozygous in two (0.5%) dogs. Twenty-two of the animals had both SOD1 mutations heterozygous (5.4%). The haplotype analysis for all BMD revealed no haplotype with both mutated alleles on a single chromosome (Figs S1 and S2). Therefore, these 22 dogs are likely to be compound heterozygous for the SOD1 haplotypes AA and TG." One of the 22 compound heterozygotes showed clinical signs of degenerative myelopathy. Summarising all available evidence, Pfahler et al. (2014) concluded that "compound heterozygosity [for the two mutations] may confer a similar risk to DM like the c.118G>A homozygous mutation". Ivansson et al. (2016) reported "that variations in SP110-mediated gene transcription may underlie, at least in part, the variability in risk for developing DM among PWCs that are homozygous for the disease-related SOD1 mutation" Mandrioli et al. (2021) reported that "three [affected Hovawart] dogs were homozygous for the c.118A allele, but none had the SP110 'risk' haplotype, suggesting a weak association of SP110 with the onset of DM in this breed. Our data suggest that the Hovawart breed is predisposed to the SOD1:c.118G>A mutation, which is associated with the development of DM."

Pathology

Histopathologic examination of the spinal cord is necessary for definitive diagnosis. Noninflammatory axonal and myelin degeneration is present at all levels of the spinal cord, being most severe in the dorsal lateral funiculus within the middle to caudal thoracic region. Segmental axonal and myelin degeneration, endoneurial fibrosis, hypomyelinated fibers and secondary demyelination are present in peripheral nerves. Axon cylinder vacuolization is characteristic (Coates et al., 2010).

Prevalence

In an extensive project, Zeng et al. (2014) genotyped 33,747 dogs representing 222 breeds for both known mutant alleles, namely c.52T and c.118A. They concluded that "the SOD1:c.118A allele is widespread and common among privately owned dogs whereas the SOD1:c.52T allele is rare and appears to be limited to Bernese Mountain Dogs." Full details are available in the paper. Mizukami et al. (2016) reported the frequency of the c.118A allele as 0.008 in 500 Border collies in Japan. Regarding the insertion reported by Turba et al. (2107), these authors reported that "The allele containing the insertion was highly prevalent in Hovawart dogs, accounting for the 26.6% of allele frequency. The insertion was also found in other unrelated breeds such as Rough Collies and Standard Poodles." Santos et al. (2020) genotyped 97 German Shepherd dogs for the SOD1:c.118G>A mutation using a PCR/RFLP test. The dogs were located in Brazil and had no clinical signs of degenerative myelopathy at the time of sampling. They “observed genotype frequencies (with 95% confidence interval) of: 0.758 (0.672-0.844), 0.242 (0.156-0.328) and 0.000 (0.000-0.000) for "GG", "AG" and "AA" genotypes, respectively.” Maki et al. (2022) genotyped 541 German Shepherd Dogs (GSD) registered with the Japanese GSD Registration Society from 2000 to 2019, for the SOD1:c.118G>A likely causal variant (omia.variant:36). They reported "330 G/G dogs (61%), 184 G/A dogs (34%), and 27 A/A dogs (5%), indicating a frequency of the mutant allele of 0.220". For each of the seven A/A dogs over 10 years old (this being an adult-onset disease), the owners reported "DM-related clinical signs, indicating a clinical progression rate of 100%".

Control

Due to the high frequency of the causative mutation in Boxers and Pembroke Welsh Corgis, in these breeds it is not practical to exclude carriers from breeding, so it is recommended that carriers be bred to noncarriers. Breeding of affected dogs of any breed should be avoided.

Genetic testing

Investigating the "many discordant findings between the parental and the offspring genotypes found by different laboratories" in testing for the c.118G>A variant, Turba et al. (2017) discovered "An insertion of 54 nucleotides [in the SOD1 gene] composed of a poly-T stretch and 15 nucleotides containing the duplication of the exon 2-intron 2 junction was . . . responsible for the partial mismatch of the reverse primer used for a direct sequencing assay. The mismatch hampered the amplification of the corresponding allele and caused an evident drop-out effect. The insertion is in complete linkage disequilibrium with the c.118G allele." Santos et al. (2020) identified “a deletion of one “T” in the position 26540247 described as ENSCAFG00000008859:g.26540247del … located in the intron 1 of the SOD1 gene. … Although the role of the ENSCAFG00000008859:g.26540247del on structure and expression of SOD1 (and consequently its relationship with CDM) was not investigated in this study, its location does not suggest that it can influence the expression of the studied disease.” However, this variant prevented in a small number of dogs adequate genotyping of the SOD1:c.118G>A in the PCR-RFLP test used in this study.

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 105400 Disease · OMIM 618598 Gene · OMIM 147450

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:000263-9615, 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. Showing 6 of 69.

Genotype and allele frequencies of canine degenerative myelopathy-associated SOD1 gene variant in Irish Wolfhound dogs. · Anim Genet · 2026 · PMID 42083737
Analysis of immune-related alterations in blood and spinal cord of canine degenerative myelopathy, a spontaneous model of amyotrophic lateral sclerosis. · Sci Rep · 2026 · PMID 41832208
Structural analysis of Cu/Zn-superoxide dismutase linked to neurodegenerative disease by antibody-guided cryo-EM. · Protein Sci · 2026 · PMID 42084503
Breed distribution of the superoxide dismutase 1 gene polymorphism associated with degenerative myelopathy in a canine population from different geographical regions of Türkiye. · Vet Med Sci · 2026 · PMID 41830531
Allele and genotype frequencies of the SOD1 c.118G>A mutation associated with degenerative myelopathy in Boxer and Pit Bull Terrier dogs from Uruguay. · Braz J Vet Med · 2026 · PMID 41867900
Correction: NanoBiT-based Analysis of Canine SOD1 Protein Dynamics: Understanding the Role of CCS and Ebselen Derivatives as Potential Therapeutics for Canine Degenerative Myelopathy. · Cell Biochem Biophys · 2025 · PMID 40478394

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 Degenerative Myelopathy (DM) and see the odds for their puppies. Single recessive variant, exact Mendelian math.

Parent A

Parent B

NNClear

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 Degenerative Myelopathy (DM) looks like in your dog's breed.

Carrier frequency by breed

Top 25 well-sampled breeds (n ≥ 50)

Maximum carrier frequency per breed across variants in the Donner 2023 cohort, with Wilson 95% confidence intervals. 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%50%100%

Fox Terrier Wire82.4% · n 182

82.4%n 182

Pembroke Welsh Corgi53.3% · n 4,364

53.3%n 4,364

Cavalier King Charles Spaniel51.0% · n 2,242

51.0%n 2,242

Boxer42.1% · n 4,552

42.1%n 4,552

Bernese Mountain Dog26.2% · n 955

26.2%n 955

Pug26.0% · n 5,154

26.0%n 5,154

Chesapeake Bay Retriever25.4% · n 138

25.4%n 138

Tibetan Terrier23.7% · n 95

23.7%n 95

American Eskimo Dog23.5% · n 302

23.5%n 302

Bloodhound22.5% · n 280

22.5%n 280

Soft Coated Wheaten Terrier21.1% · n 607

21.1%n 607

German Shepherd20.4% · n 15,645

20.4%n 15,645

Cardigan Welsh Corgi19.6% · n 125

19.6%n 125

French Bulldog19.6% · n 13,111

19.6%n 13,111

Shih Tzu17.1% · n 7,527

17.1%n 7,527

n = 55,279 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 Degenerative Myelopathy (DM) is measured; phenotype outcome depends on penetrance and modifiers.

▸ Full table with Wilson 95% confidence intervals

Breed	Carrier frequency	Wilson 95% CI	n tested
Fox Terrier Wire	82.4%	[76.2%, 87.3%]	182
Pembroke Welsh Corgi	53.3%	[51.8%, 54.8%]	4,364
Cavalier King Charles Spaniel	51.0%	[49.0%, 53.1%]	2,242
Boxer	42.1%	[40.6%, 43.5%]	4,552
Bernese Mountain Dog	26.2%	[23.5%, 29.1%]	955
Pug	26.0%	[24.8%, 27.2%]	5,154
Chesapeake Bay Retriever	25.4%	[18.8%, 33.2%]	138
Tibetan Terrier	23.7%	[16.3%, 33.2%]	95
American Eskimo Dog	23.5%	[19.1%, 28.6%]	302
Bloodhound	22.5%	[18.0%, 27.7%]	280
Soft Coated Wheaten Terrier	21.1%	[18.0%, 24.5%]	607
German Shepherd	20.4%	[19.8%, 21.1%]	15,645
Cardigan Welsh Corgi	19.6%	[13.6%, 27.4%]	125
French Bulldog	19.6%	[18.9%, 20.3%]	13,111
Shih Tzu	17.1%	[16.3%, 18.0%]	7,527
Biewer Terrier	14.9%	[10.5%, 20.8%]	184
Finnish Lapphund	14.9%	[7.9%, 26.3%]	57
Parson Russell Terrier	14.1%	[9.8%, 19.9%]	181
Boykin Spaniel	13.6%	[9.1%, 19.9%]	154
Yorkshire Terrier	13.0%	[12.3%, 13.8%]	8,367
Airedale Terrier	12.8%	[8.8%, 18.1%]	200
Bulldog Standard	12.7%	[11.8%, 13.6%]	4,816
Collie	12.6%	[10.9%, 14.6%]	1,207
Miniature Pinscher	11.2%	[9.1%, 13.9%]	658
Presa Canario	9.4%	[4.4%, 19.0%]	64

Top 25 of 102 well-sampled breeds with at least one observed carrier shown.

▸ Also observed in 36 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	Wilson 95% CI	n tested
Norfolk Terrier	76.5%	[52.7%, 90.4%]	17
Broholmer	75.0%	[44.2%, 91.9%]	10
English Toy Spaniel	75.0%	[19.8%, 97.3%]	2
Bergamasco	50.0%	[5.5%, 94.5%]	1
Poodle Medium	50.0%	[5.5%, 94.5%]	1
Portuguese Pointer	50.0%	[5.5%, 94.5%]	1
Terrier Brazileiro	30.0%	[7.3%, 70.1%]	5
Sealyham Terrier	25.0%	[4.6%, 69.9%]	4
Caucasian Shepherd Dog	23.2%	[12.9%, 38.0%]	41
Pyrenean Mastiff	20.0%	[5.7%, 51.0%]	10
Wirehaired Vizsla	16.7%	[1.8%, 69.0%]	3
Komondor	14.3%	[4.0%, 39.9%]	14
Borzoi	13.8%	[6.2%, 27.6%]	40
Czechoslovakian Wolfdog	12.5%	[1.3%, 60.4%]	4
Lakeland Terrier	12.5%	[2.2%, 47.1%]	8
American Hairless Rat Terrier	12.2%	[5.1%, 26.4%]	37
German Hunting Terrier	11.5%	[2.7%, 37.9%]	13
Tibetan Spaniel	11.5%	[4.8%, 25.2%]	39
Australian Terrier	11.1%	[2.0%, 43.5%]	9
Stabyhoun	11.1%	[3.9%, 28.1%]	27
Coonhound Black And Tan	10.0%	[1.1%, 53.7%]	5
Norwich Terrier	8.8%	[2.1%, 30.8%]	17
Irish Terrier	8.6%	[3.0%, 22.4%]	35
American Water Spaniel	8.3%	[0.9%, 48.3%]	6
Finnish Hound	8.3%	[2.9%, 21.8%]	36
Korean Jindo	8.3%	[1.5%, 35.4%]	12
Nordic Spitz	8.3%	[0.9%, 48.3%]	6
Eurasier	7.9%	[1.8%, 28.1%]	19
Kerry Blue Terrier	7.1%	[0.8%, 43.9%]	7
Kuvasz	7.1%	[0.8%, 43.9%]	7
Silky Terrier	7.1%	[2.0%, 22.6%]	28
Welsh Terrier	7.1%	[1.7%, 25.9%]	21
Mcnab	3.6%	[0.6%, 17.7%]	28
Lapponian Herder	1.9%	[0.2%, 16.0%]	26
German Pinscher	1.7%	[0.2%, 14.1%]	30
Lacy Dog	1.6%	[0.2%, 13.3%]	32

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

Scope of this record

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

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:000263-9615.
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.

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:000263-9615, authoritative clinical reference.
About OMIA, the catalogue this record comes from, and how Sniff uses it.

Last updated June 20, 2026

Sources: Sniff Atlas v1.0.1 · OMIA OMIA:000263-9615 · Donner et al. 2023