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Thrombopathia mutation identified

9K views 2 replies 2 participants last post by  Betsy Iole 
#1 ·
During the summer of 2006, the molecular basis
for BHT was determined at Auburn University. A mutation was found in a gene that encodes for
a signal transduction protein vitally important in transmitting signals that result in normal platelet
aggregation and granule release. By using DNA testing, affected and carrier Basset hounds can
now be identified by simply submitting a blood sample through the mail.[/b]
Source

We don't know the prevalence of the mutation in the breed, and imprudent elimination of carriers as breeding stock would likely result in adverse reduction of our breed's already restricted gene pool. From the above source, here are Dr. Boudreaux's recommendations for using test results:
Most of you have spent a good part of your lives trying to advance the quality of the breed and as a result
have produced some spectacular Bassets. What you don’t want to do is throw all of that effort away
because one of those dogs happens to carry a mutation for Thrombopathia. Dogs should still be bred with
the goal of producing great Bassets. If a really great Basset is also a carrier for the mutation, then go ahead
and breed but make sure to breed to a clear Basset. (I do NOT recommend breeding two known carriers).
Breeding a carrier to a clear will statistically produce a 50:50 litter (50% carriers and 50% clear,
understanding that I have seen it be 80:20 and 20:80 so the dice are not always kind) that you can hopefully
select clear dogs from to continue your line with. The puppies from such a litter should all be tested for the
mutation to identify who the carriers are. If you breed two clear bassets you don’t have to test the litter.[/b]
There has been similar DNA testing available for von Willebrand's disease in Dobermans (and other breeds) for several years. For more information on how Doberman breeders have been advised to use their dogs' screening results, see this article on applying the results of von Willebrand's DNA testing in Dobermans.

DNA Studies in Doberman von Willebrand's Disease
What should a breeder do with the test results, once they are obtained, in terms of breeding decisions? The problem facing the Doberman breeder is that it appears that only 15 to 20% of Dobermans are clear of the vWD gene. If one breeds mostly clear to clear, it narrows the breeding pool so much that there is risk of losing some of the Doberman's genetic heritage, i.e., some of the genes determining valuable positive characteristics of the Doberman might be lost, or highly diluted. Therefore, as a first priority, we advise breeding clear to clear and clear to carrier, at least for the next two or three generations. Over time, as the frequency of clear dogs increases, it should be possible to breed mostly clear to clear, and to eventually eliminate the mutant vWD gene...

Breeding carrier to affected and affected to affected should be avoided if at all possible. The first breeding produces 50% affected on average, and the second produces 100% affected animals. In my opinion, there should be two initial objectives of the Doberman vWD breeding program. One objective should be to produce as few affected animals as possible, because each is a health risk.[/b]
 
#2 ·
Thanks Betsy! All I can say is "Wow"! This is exciting news for the breed. I hope breeders will make use of this test and not say, "well it's never happened to my dogs so why should I bother?" I was always so impressed that the Otterhound breeders were able to eliminate the bleeding disorder similar to BHT from their breed. Of course if basset breeders don't share test results then it's not likely thrombopathia will cease to exist in basset hounds.
 
#3 ·
I believe it was the same investigator who discovered the mutation in Otterhounds, Mary Boudreaux. :)
 
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