here on information on DM. It's a VERY hot topic with a lot of breeders in the US (still being totally ignored by show breeders in Europe at this time) But A LOT Of the info out there is seriously flawed and there are A LOT of misinformed people. Ok - First off. What is DM? Degenerative myelopathy (DM) is a progressive disease of the spinal cord in older dogs. The disease has an insidious onset typically between 8 and 14 years of age. Pembroke Welsh corgis are one breed that is at higher risk for DM due to their longer spinal cords and a genetic predisposition in the breed for the condition. What causes DM? DM, like most degenerative conditions has a wide variety of causes and triggers. Genetics of course play a role, with injury, exercise, overall health and nutrition also being key factors. Recent research has identified a mutation in a gene that confers a greatly increased risk of developing the disease. This mutation does not have a simple Positive or Negative test result that can be easily assigned to each dog. Instead the genetic test result gives us a break down of "At Risk to Develop DM, Carrier, and Clear" These three results break down to the following. At Risk dogs have two copies of the gene thought to develop the DM gene. They are at potential risk, but that in no way means they will get DM. It means they have the potential to develop DM if combined with outside factors. Carrier means that while the dog caries one copy of the genetic mutation to develop DM they themselves will most likely never have the condition themselves, but they could potentially pass this gene on to their offspring. Clear means the dog does not contain two copies of the gene BUT still may be at risk if outside factors present. Currently in the US 52% of all Corgis are DM At Risk. 37% are Carrier, and only 11% are Clear. Meaning that a HUGE majority of corgis are at risk for this condition but only a TINY number of those will ever actually develop DM, and most of those will be due to outside factors combined with genetics. OFA recently updated their DM breeding guide to read " 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." (An interesting note on this gene that is linked to DM in corgis. This same gene appears in up to 90% of Fox Terriers at risk or Carrier) yet there has never been a single case of DM reported within that breed, which live a very long time. Basically Dm testing is very flawed still! We dearly wish we could get a simple test that says Yes, this dog WILL have this condition, or NO this dog will not ever develop this condition. But that is no where near the test we currently have for DM. The test results now can say that a Dog most likely will not have DM as long as no outside factors come into play (DM Clear dogs have been known to still develop DM under those conditions) and Dm At Risk dogs (making up the largest portion of the corgi breed) will most likely NOT have DM as long as no outside factors come into play. Of all Corgis (regardless of test results) less than 2% (Current numbers are 1.51%) total will ever develop DM. Which in itself is a fact that MOST people ignore or do not realize. And also fail to consider exactly how much of that 1.51% is actually due to genetically linked DM and how much is outside factors (bad nutrition, bad exercise, or injury related!)
DM- Ok, well I'm going to say I'm sorry in advance on writing a book
So our take on DM testing! -- Dm testing has a long way to go to be a real tool in a breeding program. Dogs have been reported who have developed DM even when they have been tested as Carrier or Clear/Normal. These diagnoses of DM were confirmed by necropsy and examination of the spinal cord. This study which can be read at http://onlinelibrary.wiley.com/doi/10.1111/jvim.12317/full Outlines dogs that were tested to have DM while being DM Clear or DM Carrier. Meaning that the DM test result of Clear which is so highly coveted by some breeders, may not be worth the paper the test is printed on, as if a DM Clear dog can still develop DM then the test is worthless. In one case, the dog had a different mutation at the SOD1 locus, which confirms that more than one form of DM exists, and more than one gene is involved. It should for sure be a consideration and lines with known genetically linked DM cases should never be bred. As OFA states, breeders who decide to exclude anything but DM clear dogs in their programs will destroy the corgi breed entirely by doing so. Dm testing is important, but at the same time, it's one of MANY factors that good breeders should take into consideration. It is not a MAJOR factor. I have spoken to many breeders over the last two years on the topic of DM....I have been offered the chance to own several DM clear puppies. Many from lines that are pet quality at best, or have serious faults or issues that would deem them to be pet quality only if not for the fact that they are DM clear therefore suddenly considered breeding quality! Dm Clear is fast being the #1 concern with breeders, and it's absolutely silly for that to be the truth! There are SO many factors that breeders should be considering in combination with DM test results, but that they are ignoring instead in favor of getting a DM clear result. Our goal as breeders is to produce the total package. Outstanding health, amazing temperament, super longevity, intelligence, and beauty! The perfect puppy to be a family member or the star of the show ring. A great farm companion or a buddy on your every adventure! We do DM testing on our corgis, and believe that generations down the road the test results will help make a better guide to following and ruling out types of DM (Outside factors causing DM or Genetically linked DM)
Our lines are from lines with excellent genetic health, and NO genetically linked DM or ANY other DM for that matter. We personally have kept At Risk puppies from litters where clears are available, and have recently imported several puppies from Europe with NO Dm testing in the entire pedigree or the puppy. DM is not a concern at all in Europe to date, as several years back a DNA test was developed for a small health condition in another breed, and it almost entirely wiped the breed out of existence, so they are extremely caution about letting small health concerns snowball into panic attacks that destroy a breed entirely.
Other GREAT Articles on DM