Dog Degenerative Myelopathy Genetics

Understanding the genetic basis of canine degenerative myelopathy allows breeders to reduce disease prevalence through testing and informed breeding decisions.

Key Facts

A mutation in the SOD1 gene (c.118G>A) is associated with DM in over 120 dog breeds
Homozygous affected dogs have much higher risk of developing clinical DM than heterozygous carriers
Not all homozygous dogs develop DM, suggesting additional genetic or environmental modifying factors
DNA testing identifies at-risk genotypes before clinical disease develops
German Shepherd Dogs, Pembroke Welsh Corgis, Boxers, and Chesapeake Bay Retrievers have high prevalence
Breeding two carriers together produces statistically affected offspring that will suffer from the disease

Welfare Considerations

DM causes progressive hindlimb paralysis and eventual full body weakness representing a significant and prolonged welfare burden. The condition is invariably fatal within one to three years of clinical onset. Genetic testing allows breeders to make informed decisions that progressively reduce the proportion of at-risk animals in breed populations. Breeding from two carriers when a clear alternative exists is a welfare-relevant decision because the resulting affected offspring will face a difficult progressive disease. Breed health schemes that encourage testing and clear pairing strategies can substantially reduce future DM prevalence.

What You Can Do

Test breeding animals from at-risk breeds for the SOD1 DM mutation before pairing
Avoid pairing two carriers if alternative matches are available to prevent producing affected offspring
Inform purchasers of offspring from carrier parents about the genetic risk and monitoring requirements
Support breed health committees in developing DM prevalence reduction programmes
Donate to canine neurological disease research seeking treatments that could slow DM progression