Genetic Testing Info to Consider

A common question in the corgi world today is, do you DM test? 

It is the new craze and one of the reasons puppy prices have suddenly shot up. 

The problem?       It's not fully understood or accurate and this new fad is causing many breeders to test for DM without regard to any other genetic issues that could be going on! 

This is very concerning. Nessa Gier, a show breeder, explains it beautifully!

Here's what she has to say on DM:

​"​DM- Ok, well I'm going to say I'm sorry in advance on writing a book 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 clearly
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!)

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 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 health, and longevity.  DM is not a concern that should be overemphasized beyond reasonable consideration, 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. "Testing is important. We need to use it to further gain information as to what truly causes DM and how to prevent it. For now, if you purchase that at risk or untested puppy, keep in mind that you are not at anymore risk of DM than purchasing any other puppy. Don't let DM results strictly define which puppy you buy as it could prevent you from buying a quality puppy.

• Article from Carolina Veterinary Specialists
• German Article
• UK Article

Due to DM being so similar to ALS in people, further research is currently under way to hopefully not only prevent/treat DM but also ALS in people. There is also more research going on as far as the testing itself and which genes and proteins are involved. Hopefully we will have more answers some time in the near future!
Here are some links about recent studies and research:

Possible Treatment For DM

A Problem Found with DM testing procedures