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CANINE CYCLIC NEUTROPENIA
(Used with permission from Michelle Tennis, Bit O' Heaven Collies)
Several picture can be seen on Michelles site www. Bitoheavencollies.com click on the Grey Collie
link
DESCRIPTION Canine Cyclic Neutropenia is a stem cell disorder
that occurs in collies. Puppies are usually smaller and weaker than their litter mates and by 8 to 12 weeks of age they develop
clinical signs such as fever, diarrhea, joint pain, or other signs associated with eye, respiratory, or skin infections. The
disorder is caused by an abnormality of the stem cells in the bone marrow, from which all blood cells are developed. The result
is a cyclic fluctuation in blood cell numbers. Every 10 to 12 days the number of neutrophils drops dramatically, and then
rebounds.
There is an increased susceptibility to infection corresponding to the dip in neutrophil numbers.
Affected dogs are subject to severe recurring bacterial infections, primarily of the respiratory or gastrointestinal tract.
These dogs are also prone to bleeding episodes due to the drop in blood cells numbers. This is a serious genetic disorder.
Even with the best of care, affected dogs rarely live beyond 2 or 3 years of age. Most die within the first few weeks.
The disease occurs in all gray (not merle) collies. Affected puppies have a silver gray hair
coat that ranges in color from very light, to darkish pewter gray, sometimes with a slight yellowing due to a mixture of light
beige and light gray hair. No matter what color variation or type, all Collies have black noses EXCEPT those with gray collie
syndrome. If the nose continues to come in gray, then that is pathognomonic (absolutely diagnostic) for "gray collie syndrome".
Sable "gray collie syndrome" dogs have brown or pale sable noses, but never black noses as they should have.
Note from Dr. William Osborne:
Sugar is currently being treated with recombinant canine G-CSF to determine her production
of neutrophils in response to this hormone. When we have established a dose-response relationship to the G-CSF we will
administer intramuscularly a lentivirus encoding canine G-CSF gene to deliver life-long therapy. We have treated two
grey collies with single administrations of G-CSF-lentivirus and they both were cured of their recurrent neutropenia and remained
healthy for over 18 months.
Note from Dr. William Osborne:
We completed the dose escalation of recombinant G-CSF and obtained a nice response.
She is doing extremely well! She now weighs 30 lb and received lentivirus last Tuesday. Her WBC counts are now
up to 50,000 cells/ul. This response to treatment is beyond anything we have observed before.
Note from Dr. Osborne:
Slide 1
Sugars average cell counts before treatment, when she was cycling, were 2,090 cells/µl.
After virus administration her average cell counts are 26,000 cells/µl. As you can see (per Slide 1) she has an abundance
of neutrophils and this would account for her being free of infections and fever.
Sugar came back home on May 23rd, 08. She turned 3 years old on May 25th. The
photos above were taken on May 24th. We will put up more information about her treatment when we receive it.
A sure sign of GCS is lack of pigment on the nose. A gray collie will have a gray
or brown nose rather than black. "Gray Collies" will also lack tan markings on the face and body but this can also happen
in the "white merle". A normal Blue Merle or Tri will have typical tan markings on the face.
A sable will be almost completely white. Above is a photo of an 8 week old sable merle
"gray".
Questions?
If you have a carrier, your dog will be perfectly healthy in every respect and you should not fear for
him. BUT if you bred to another dog that carries this same gene, you not only run the risk of producing an Affected Gray puppy,
you will be sure to produce other carriers.
Visit HealthGene and get the whole story on the mode of inheritance and the testing that they offer.
HEALTHGENE WEB SITE
There is also a new open data base where you can list your DNA NON-CARRIER, or look through the data base
to see if the breeding partner you want is listed. If the dogs that you would like to use are not there, ask them to test
and put the dog's name there for all to see. Only DNA NON-CARRIERS will be listed.
CLEAR COLLIE REGISTRY
Go to the home page, go to messages, and you can search on the kennel name you are looking for. The name
of the dog will be in the subject line and the test results and certificate numbers will be in the body of the message. No
one can post to this list but the owners. Send your non-carrier test result to the list owner for inclusion in the data base.
It is open for anyone to join and search though. Of course there is no charge for any of this. This data base will be up and
totally running by July 1, 2005.
This database will also list favorable results for the MDR1 Drug Sensitivities in Collies DNA tests and Optigen CEA test for Non-Carriers of Collie Eye Anomaly. The data base will include DNA test results for additional conditions as they become available. HealthGene is working on
a DNA marker for Epilepsy now. We will keep going until we get PRA next.
We now have another tool to use when planning our breedings. GCS is not long gone as many breeders think
it is. It's alive and kicking butt in many of today's major breeding kennels. Where did it come from? It came from everywhere
in the beginning. Many breeders had to test breed and eliminate the known producers while they continued to use siblings that
were carriers without even knowing it.
Are they at fault? No, They did the best with what they had, but they had no test and they only had half
the information on the mode of inheritance. We are living in a different age now. We have DNA markers that tell us exactly
where we stand with our breeding dogs. Useful information that will take us even further that we ever thought possible in
the continued battle against genetic problems. What can we do now? We can test and going forward, clear our lines of this
lethal gene.
Does this mean that no carrier should ever be bred? No, that's not what we are saying. There are many magnificent
show dogs that excel in qualities that signify what a Collie Should be. We can't limit the gene pool from these great dogs.
What we can do is take a non-carrier to this dog, select the resulting get carefully and test the ones that carry on those
virtues. You can then use the non-carriers back into the breeding program. All those not kept should be spayed/neutered and
placed in good companion homes. Remember, the carriers themselves are perfectly healthy.
However; with the beginnings of a non-carrier data base, we should be able to find similar dogs that do
not carry this gene and just be done with it. As for me personally, I've spent over a thousand dollars testing all my breeding
dogs and I'll never again breed to a carrier. As long as I am careful in my selection of partners, breeding non-carriers only,
signified by the DNA status, I should never have to test again. I would rather spend the money once and start with cleared
breeding dogs, than to continue to worry about this generation after generation. All our puppies and adults offered for breeding
are from DNA-non carrier dogs.
Here is another web page that offers information regarding drug sensitivities Veterinary Clinical Pharmacology Laboratory
by Peggy Melton and Michelle Tennis)