One of the top questions we get asked is whether our dogs have been tested for Degenerative Myelopathy (known as DM) and if the puppies will be affected. We believe this is an important issue to research and understand as you prepare to purchase a corgi puppy, and as breeders we take it very seriously and work hard to produce healthy dogs. All of our breeding corgis have a known DM status (see Our Corgis page for more information) and we carefully breed to only produce puppies that are either DM Clear or DM Carriers.
The following is from a PetMD article describing DM:
What is degenerative myelopathy?
Degenerative myelopathy of dogs is a slowly progressive, non-inflammatory degeneration of the white matter of the spinal cord. It is most common in German Shepherd Dogs and Welsh Corgis, but is occasionally recognized in other breeds. The cause is unknown, although genetic factors are suspected.
Affected dogs are usually greater than 5-years-old and develop non-painful weakness of the hind legs that causes an unsteady gait. Early cases may be confused with orthopedic injuries; however, proprioceptive deficits (inability to sense where the limbs are in space) are an early feature of degenerative myelopathy and are not seen in orthopedic disease. Signs slowly progress to paralysis of the back end of the body over 6-36 months, although severity of signs may fluctuate. An MRI or CSF analysis is performed to rule out other causes of spinal cord dysfunction.
DM is a tragic genetic disorder, and, thankfully, in 2008 the responsible gene was discovered which now allows testing to be done and a responsible breeding program to be established. (OFFA offers this test for anyone for $65 and it is a simple cheek swab that can be done at home and mailed to their labs.) However, it is notable that DM is still not fully understood and there are unknown outside factors that play a role. So, while we believe that it is vital to know our dogs DM statuses and to breed responsibly – to the best of our abilities – we do not place over-confidence in the test results and instead aim to select our dogs for overall quality with general health, family friendly personalities and desirable breed standards in mind.
As it states on the Orthopedic Foundation for Animals (OFFA) website:
The “A” (mutated) allele appears to be very common in some breeds. In these breeds, an overly aggressive breeding program to eliminate dogs testing A/A or A/N might be devastating to the breed as a whole because it would eliminate a large fraction of the high quality dogs that would otherwise contribute desirable qualities to the breed. Nonetheless, DM should be taken seriously. It is a fatal disease with devastating consequences for the dog, and can be a trying experience for the owners that care for them. A realistic approach when considering which dogs to select for breeding would be to treat the test results as one would treat any other undesirable trait or fault. Dogs testing At-Risk (A/A) should be considered to have a more serious fault than those testing as Carriers (A/N). Incorporating this information into their selection criteria, breeders can then proceed as conscientious breeders have always done: make their breeding selections based on all the dog’s strengths and all the dog’s faults. Using this approach and factoring the DM test results into the breeding decisions should reduce the prevalence of DM in the subsequent generations while continuing to maintain and improve upon positive, sought after traits.
We recommend that breeders take into consideration the DM test results as they plan their breeding programs; however, they should not over-emphasize the test results. Instead, the test result should be one factor among many in a balanced breeding program.
This sums up our views very well. Below is a Punnet Square laying out the possible breeding outcomes resulting from the various DM parental statuses:
Because of the many unknowns still present in the current research on DM we do not promise across the board that our puppies will never develop DM. There have been a couple documented cases of DM Clear dogs still contracting the disease. However, that being said: It is generally understood that DM Clears will not develop DM, DM Carriers will not develop DM but could pass the mutated gene onto their offspring, and DM At Risks have the potential to develop DM.
Also, there has been one small scale study that showed only 30% of At Risk Dogs developed DM — though that should be taken with caution given the scale of the study (only 17 dogs were tested). OFA published statistics showing that in the United States 52% of tested Pembroke Welsh Corgis are At Risk (AA), 37% are Carrier (AN) and 11% are Clear (NN). This means that the vast majority of puppies available are going to be either At Risk or Carriers.
Dr. Mayer, in an article for Welsh Corgi News, made this statement about DM Carriers:
“…a Carrier pup is a fine pet and will not get DM, and reserve any Clears that are breeding quality as breeding stock.”
Education and awareness are key for both corgi breeders and puppy buyers.
Below are other articles discussing DM: