Responsible breeding for degenerative myelopathy starts long before a litter is born — it starts with a cheek swab and a commitment to honest record-keeping.

Quick answer: Responsible breeders screen for degenerative myelopathy primarily through SOD1 genetic testing, which identifies dogs carrying the mutation most strongly associated with DM. Results are categorized as clear, carrier, or at-risk (two copies). The goal is to avoid producing puppies that are homozygous at-risk — meaning they carry two copies of the mutation — by pairing clear or carrier dogs intentionally. Breeders also register results in the OFA database, participate in breed-club health programs, and disclose results transparently to buyers. No single test eliminates DM risk entirely, but systematic screening meaningfully reduces the odds of producing affected dogs.

Degenerative myelopathy is one of the most heartbreaking conditions in the dog world — a slow, progressive neurological disease with no cure and no treatment that reliably slows it. Understanding the genetics behind DM doesn’t make it easier to watch a dog lose function, but it does give breeders a real tool for reducing how often the disease appears in future generations.

If you’re researching a breeder, planning a litter, or trying to understand why the puppy question matters, this is what responsible screening actually looks like.

What Is the SOD1 Test and Why Does It Matter?

The SOD1 test identifies variants in the SOD1 gene — specifically mutations associated with degenerative myelopathy in dogs. The research behind this test originated at the University of Missouri College of Veterinary Medicine, where scientists identified that a mutation in the SOD1 gene (now called the SOD1 A allele) was strongly linked to DM across many breeds.

Dogs are tested and classified into three categories:

  • Clear (N/N): Two normal copies of the gene. This dog is not at elevated genetic risk and cannot pass the mutation to offspring.
  • Carrier (N/A): One normal copy and one mutated copy. Carriers are not typically expected to develop DM themselves, but they can pass the mutation to their puppies.
  • At-risk (A/A): Two copies of the SOD1 A mutation. This dog has a significantly higher probability of developing DM during its lifetime.

A second mutation, SOD1 B, has also been identified and is relevant in certain breeds, particularly some large and giant breeds. Breed-specific guidance from health committees will specify whether testing for both variants is recommended.

The test itself is simple: a cheek swab or blood sample, sent to a laboratory. Results are permanent and do not change. The Orthopedic Foundation for Animals accepts and publishes SOD1 results, making them searchable in a public database.

What SOD1 Results Actually Tell You
  • Clear (N/N) dogs cannot pass the mutation to puppies
  • Carrier (N/A) dogs can produce at-risk puppies if paired with another carrier or at-risk dog
  • At-risk (A/A) dogs have elevated DM probability but may not develop clinical disease
  • A second mutation (SOD1 B) exists — check your breed club for guidance on whether to test for it

How Do Responsible Breeders Use These Results?

Responsible breeders use SOD1 results to guide pairing decisions — not to eliminate every dog from a breeding program, but to avoid producing at-risk (A/A) puppies.

The math is straightforward:

  • Clear × Clear: All puppies will be clear. No DM risk passed on.
  • Clear × Carrier: Puppies will be clear or carrier, roughly half and half. No at-risk puppies produced.
  • Carrier × Carrier: Statistically, one in four puppies may be at-risk. Most responsible breeders avoid this pairing or move carefully.
  • At-risk × Any: Can produce at-risk puppies depending on the partner’s result.

The practical result is that many thoughtful breeders work toward reducing the overall frequency of the mutation in their breeding lines over generations, pairing carriers with clear dogs rather than eliminating carriers entirely (which in some breeds could severely restrict the gene pool).

For a deeper look at what the SOD1 test results mean for individual dogs, our article on the SOD1 genetic test for DM walks through the nuances — including why a clear test result doesn’t guarantee a DM-free future.

What SOD1 Testing Cannot Do
  • It cannot guarantee a dog will never develop DM — other genetic and environmental factors exist
  • It does not replace clinical monitoring as dogs age
  • A “clear” result means no elevated genetic risk, not a certainty of lifelong neurological health
  • Breeds with low SOD1 prevalence may still develop DM through mechanisms not yet fully characterized

The OFA Database and CHIC Programs

The Orthopedic Foundation for Animals maintains the largest public database of canine health test results in North America. When a breeder submits SOD1 results to OFA, those results become publicly searchable — which means anyone can verify a dog’s test status before purchasing a puppy or committing to a breeding.

This transparency is the backbone of responsible breeding programs. It removes the ability for results to be quietly ignored or selectively disclosed.

What Is the CHIC Program?

CHIC (Canine Health Information Center) is a program co-managed by OFA and individual breed clubs. To earn a CHIC number, a dog must complete all health tests required by its breed club and have those results publicly available. The specific tests required vary by breed — some breed clubs include DM SOD1 testing in their CHIC protocol; others don’t yet.

If you’re buying a puppy from a DM-susceptible breed, ask whether the parents have CHIC numbers and look them up directly on the OFA website. A CHIC number is meaningful because it confirms the dog met the full panel of health requirements, not just cherry-picked ones.

Which Breeds Should Be Prioritized?

DM has been identified in a wide range of breeds, but it appears most commonly in German Shepherds, Pembroke Welsh Corgis, Boxers, Chesapeake Bay Retrievers, Rhodesian Ridgebacks, and several others. Standard Poodles and their mixes are also a known population. Our article on DM in Doodle mixes covers how the Poodle genetic legacy passes through mixed-breed lines.

What to Look For in a Responsible Breeder
  • Both parents have OFA-verified SOD1 test results (searchable online)
  • Breeder can explain the pairing decision in terms of genetic risk
  • Results are shared openly without prompting
  • Breeder participates in breed-club health programs or mentorship networks
  • Breeder asks you questions too — they want to know where their puppies are going

Breed-Club Health Programs and Registries

Breed clubs play a critical role in making genetic screening normal rather than exceptional. The best clubs don’t just recommend testing — they educate breeders, track prevalence data over time, and sometimes fund research into the conditions affecting their breed.

What active breed-club health programs typically include:

  • Published testing protocols: Clear guidance on which tests are required or recommended at what age
  • Health surveys: Periodic data collection on disease prevalence within the breed population
  • Breeder education: Seminars, webinars, and written resources explaining the genetics
  • Mentorship programs: Pairing newer breeders with experienced ones who model responsible practices
  • Research partnerships: Collaboration with veterinary schools and organizations like the Canine Health Foundation to fund ongoing DM research

If a breed club for a DM-susceptible breed has no health testing protocol and no published guidance on SOD1 testing, that’s a gap worth noting — and asking breeders within that community about directly.

Should You Breed a Dog That Is a SOD1 Carrier?

This is one of the most common questions in the breeding community, and our full article on whether to breed a SOD1 carrier covers it in detail. The short version: in many breeds, carriers can be bred responsibly if paired with a clear dog, because no at-risk puppies will be produced from that pairing. Eliminating all carriers in one generation can cause other genetic problems — reduced diversity, founder effects, increased risk of other heritable conditions.

The goal is gradual, generation-by-generation reduction of mutation frequency without bottlenecking the breed.

What Does Transparent Disclosure Look Like?

A breeder who takes DM screening seriously will discuss the test results of both parents in straightforward terms. They will explain what the results mean for puppy risk. They will share or point you to the OFA records directly rather than just saying “the parents were tested.”

They’ll also be honest about the limits of testing — that a clear result reduces but doesn’t eliminate all DM risk, and that DM remains a possibility in any breed where the mutation is present.

From what I’ve seen in the disabled dog community and in conversations with caregivers, the breeders who are most forthcoming about health testing are also the ones most likely to stay in contact with puppy buyers over the dog’s lifetime. That ongoing relationship matters — both for flagging health concerns early and for the kind of informed breeding decisions that happen years down the line.

If you’re buying a puppy from an at-risk breed and the breeder can’t point you to OFA records for both parents, it’s reasonable to ask directly. A companion article on questions to ask breeders before buying from an at-risk breed gives you a more specific list.

Screening before breeding isn’t about eliminating dogs from programs or attaching stigma to a positive result. It’s about making informed decisions with the tools we have — tools that, used well, can genuinely reduce how many families sit where DM caregivers sit today.

Frequently Asked Questions

Can a dog with two copies of the SOD1 mutation definitely develop DM?

Not necessarily. Having two copies of the SOD1 A allele (homozygous at-risk) significantly raises the probability of developing DM, but research suggests other genetic and environmental factors also play a role. Many homozygous dogs live long lives without clear DM symptoms, though the risk is substantially higher than in dogs with one or zero copies.

Is SOD1 testing the only genetic screen breeders need for DM?

It is the primary test used today. The SOD1 B mutation was later identified as a second DM-associated variant, particularly in some large breeds. Responsible breeders in affected breeds test for both mutations when breed-specific guidance recommends it. Your breed club’s health committee is the best source for current recommendations.

What is the OFA CHIC program and does every breed participate?

The Canine Health Information Center (CHIC), managed by the Orthopedic Foundation for Animals, maintains a database of dogs who have completed a breed-specific health testing protocol. Participation requirements vary by breed — not every breed includes DM SOD1 testing in their CHIC protocol, so check your specific breed club’s health committee page.

Can I ask a breeder for proof of SOD1 testing before buying a puppy?

Yes, and you should. Reputable breeders will readily share OFA test certificates or the official results page for both parents. If a breeder is evasive about test results or claims the dogs are “too young” to test (the SOD1 test can be run at any age from a cheek swab), that is worth noting carefully.

This guide is based on real experience and should be used alongside professional veterinary care. Always consult your veterinarian before starting any new treatment or making changes to your dog’s care plan.