DM testing - Page 1

Pedigree Database

 

by jprony on 30 September 2015 - 05:09

I've been told by a breeder that buys dogs from Germany that Germany does not DM test their dogs because the DM gene found to effect other breeds is not what causes it in gsd. Anyone hear the same or different information about DM testing specifically in gsd' s?

Hundmutter

by Hundmutter on 30 September 2015 - 06:09

Do a Search of the PDB Site, you will find a number of threds on DM
and the Tests cached, with comparative info. Not much used in Germany
and the rest of Europe because, as you have heard, there are different
strains of the disease, affecting different breeds. Also there are some
tested negative dogs that have still gone on to develop DM, as I under-
stand the US situation.
Degenerative Myelopathy is an extremely difficult thing to diagnose,
because its symptoms cross-refer to so many other spinal & nerve
problems; also the only way to be sure a dog had it, is on post mortem.
Even given the imperfections around testing as yet, the concensus seems
to be starting to be : better to test and get dodgy results than to do nothing
and cross you fingers in the dark ! I believe we should test, because using
the test supports the ongoing work, keeps the topic to the fore, etc.
Better still, throw any spare money you have towards continuing Research.

bubbabooboo

by bubbabooboo on 02 October 2015 - 15:10

Inconclusive results are worse than no results if acted upon. Variants and results that do not track with the genetics linked disease are actually harmful to both the patient and the diagnosis and should be ignored if based on inconclusive variants or scientific understanding. Even well understood gene variants such as the BRAC gene in humans do not track with breast cancer one hundred percent, the presence of the BRAC variant simply indicates a higher risk of developing breast cancer than in those patients without the variant. A family history of breast cancer in combination with the BRAC variant is usually how the variant is diagnosed. Plenty of women with the BRAC variant that never have breast cancer. If humans chose to sterilize every woman with the BRAC gene variant that would not eliminate breast cancer and it would likely not eliminate the BRAC variant. Women with the BRAC variant that is known to carry a higher risk ( but not certainty of breast cancer ) and which have a history of breast cancer in their family tree are counseled to get more frequent testing, also if they wish they they are counseled that they can choose to have their breasts removed as a precaution. However it is well known that not all women with the BRAC variant ( sometimes called mutation ) will develop breast cancer. Selection against a genetic variant can also lead to unexpected results such that selection against or for one genetic variant may increase or decrease the frequency of other traits or genetic variations both good and bad. Selective breeding based on an incomplete knowledge or false causation of a genetic disease may result in the increase of genes responsible for other diseases or genetic traits that are equal or worse in their result.


by Blitzen on 02 October 2015 - 15:10

Sounds like the same excuses for not titling. Not too many years ago GSD breeders were arguing against xraying hips and later, elbows. The upside for breeders in the US is that they can breed GSD's without any health tests whatsoever. The upside for the buyers is they can buy them or not.

It may not be too far in the future that Germany requires DM tests. Some in Germany are testing now. I can't wait to hear the excuses then.

Why wouldn't a breeder want to take advantage of all tests that are breed specific and use the results accordingly?


by Nans gsd on 02 October 2015 - 16:10

$

susie

by susie on 02 October 2015 - 16:10

"Why wouldn't a breeder want to take advantage of all tests that are breed specific and use the results accordingly?"

Because in that case breeders would need to weed out some of their breeding stock...
As long as tests are not mandatory, be it HD, ED, spine, DM, affected dogs are allowed for breeding.
Think about a puppy raised for two years, in the best case even trained and titled, and it doesn´t pass the tests - a lot of MONEY lost.

Bubba, out of interest, do you know how high is the percentage of women who developed breast cancer WITHOUT having the BRAC variant?

Hundmutter

by Hundmutter on 02 October 2015 - 16:10

Not sure what Bubs means about "acting on" inconclusive results, in this
case. The only action which could be taken on a positive DNA test
result is to refrain from breeding that dog. How many times does it need
to be said that the GSD is NOT a species threatened with extinction ? A
few less being produced would almost certainly be a good thing, looking
at the numbers ending up in shelters.

Conversely a clear / normal test result IF TREATED AS LESS THAN 100%
RELIABLE may result in a litter being produced, but if nobody is fooled into
believing their puppy ABSOLUTELY CANNOT GROW UP TO HAVE DM,
OR PRODUCE OFFSPRING WITH DM, i.e. everybody is educated to
understand the clear certificate may be right, (in which case, great !) or it
may be wrong, there are no guarantees, then no one is in any WORSE
position than we were before the Test was available.

bubbabooboo

by bubbabooboo on 02 October 2015 - 17:10

If following a human genetic testing protocol the test for DM would only be done for individuals at high risk due to a family history of DM and then the results would only be used as a caution against breeding the dogs clearly positive for the variant. Genetic testing as it currents exists is much better at explaining diseases and birth defects than predicting them. The OFA approach is flawed because it attempts to predict next generation results based on testing parents and eliminating them from the breeding population. This is known to be difficult or impossible in humans with the exception of some very simple single gene variants which are exceedingly rare in the general population. There are no examples that I can think of in which human parents are routinely tested for a genetic mutation or variant unless a family or historical record of the disease or defect is known to exist in that group. Even though we know what causes Down's Syndrome we can only detect it in a fetus or individual ... it can not be predicted from testing the parents. According to the flawed logic of this board's pseudo scientists and the OFA, all women with a BRCA mutation should not have children. There are plenty of children to adopt ( which may or may not have the BRCA variant ) and if we just eliminate the BRCA genetic mutations breast cancer will become extinct. However we know that is not the case even in a well studied and researched genetic variant such as BRCA. However the picture for DM is far from being as clear as what we now know or think we know about the BRCA genetic variants. DM is not a simple single gene variant so there is no reason to base breeding decisions on data and research that is flawed or incomplete. Even in the case of the well studied BRCA variants what is known is that the vast majority of women who develop breast cancer do not have a BRCA mutation. Even among women with the BRCA variants there are 40-50% who will not develop breast cancer.

Because harmful BRCA1 and BRCA2 gene mutations are relatively rare in the general population, most experts agree that mutation testing of individuals who do not have cancer should be performed only when the person’s individual or family history suggests the possible presence of a harmful mutation in BRCA1 or BRCA2.

A woman’s lifetime risk of developing breast and/or ovarian cancer is greatly increased if she inherits a harmful mutation in BRCA1 or BRCA2.

Breast cancer: About 12 percent of women in the general population will develop breast cancer sometime during their lives (4). By contrast, according to the most recent estimates, 55 to 65 percent of women who inherit a harmful BRCA1 mutation and around 45 percent of women who inherit a harmful BRCA2 mutation will develop breast cancer by age 70 years (5, 6).

It is important to note that these estimated percentages of lifetime risk are different from those available previously; the estimates have changed as more information has become available, and they may change again with additional research. No long-term general population studies have directly compared overall cancer risk in women who have and do not have a harmful BRCA1 or BRCA2 mutation.

susie

by susie on 02 October 2015 - 17:10

"Even in the case of the well studied BRCA variants what is known is that the vast majority of women who develop breast cancer do not have a BRCA mutation."
"A woman’s lifetime risk of developing breast and/or ovarian cancer is greatly increased if she inherits a harmful mutation in BRCA1 or BRCA2."

???????????????????????

Okay, we are talking about DOGS, not about humans, that said, EVERY breeding is not made because of of love between two dogs, but because of consideration of the breeder. We are not talking about nature, but about the breeders CHOICE. There is the main difference.

I am still waiting for the names of the dogs who got DM ( proofed after death ! ) without being the result of breedings out of carriers or at risks. Maybe there are dogs, but honestly, we are not talking about nature, but about purposeful breeding = at least I would try to eliminate as much preconditions as possible ( no carrier/carrier, no at risk ). There are are thousands of thousands of German Shepherd dogs on this world, don´t tell me, this would narrow the gene pool too much.

Forget about Down´s Syndrome, maybe one day we´ll be able to test for it, but as long as there is no test available, there is no comparison possible.



by Blitzen on 02 October 2015 - 18:10

I said "use the results accordingly" which doesn't mean eliminating dogs without considering their pedigrees, prior history of production, etc. I have said here many, many times I would use an at risk for breeding but would  breed it to a DM normal dog. Given there is no shortage of GSD's in this world, I can't imagine I could not find a suitable DM normal dog.  It might not be sitting in my backyard and that could be a determent for some.The next issue is placing the pups sold for breeding. They would all be carriers, so that would entail more work for the breeder.  Other breeders do it and have done it for years and  years. If breeding good and healthy GSD's were simple and easy, there would be a lot more of them.

I'd rather know what I was dealing with than go into breeding a litter with only half of the available information. What's the point of not knowing? Most health tests, including the DNA DM test,  are not intended to be used to eliminate any dogs from breeding programs. They are intended to help breeders choose the best breeding stock they can and to avoid breed specific diseases when possible and if applicable. What could be wrong with that?

The chance of losing money on a dog is part of the game.






 


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