TESTING FOR HEREDITARY EYE DISEASES IN SIBERIAN HUSKIES
Plus tests performed so far on our
own dogs
(written April 27, 2008 by Katerina Paleckova)
Last year (August 2007), when I wrote a tribute to our beloved dog
Kipp, who died due to glaucoma caused blindness, and suffered from pain,
caused by this disease, I promissed to one day write a bit more about
glaucoma, other hereditary eye diseases, the testing that can be performed,
and mainly HOW we all can avoid the unnecessary suffering of our animals.
We just came back from another eye testing session, organized by
Jämtland/Härjedalens Kennel Club in Östersund, in cooperation with certified
veterinary eye specialist, Dr.Nils Wallin Hĺkanson.
This time I
prepared some questions for Dr.Hĺkanson, in order to be able to share some
basic information in form of the following notes. They generally concern
gonioscopy.
Please note, that these notes were made not to criticise
anyone, and also that they are not "perfect". They are my own notes as I put
together the answers Dr.Hĺkanson generously gave me. None of them are
quoting him either!
The term "narrow angles" in a result of a
gonioscopy test, performed by certified opthalmologist, reffer to narrow (or
underdeveloped) chamber angles in the eye. The degree of underdevelopment
(goniodysgenesis) is often listed as either "mild", "moderate" or "severe".
Some "severe" results may also include comment such as "changes occuring",
which basically reffers to the start of changes in the eye, signalling
development of glaucoma.
Generally goniodysgenesy is a defect, while
glaucoma is a disease.
Narrow angles (not talking about severly
narrow or with changes already occuring in the eye) are relatively common in
the siberian husky breed and do not necesairly mean the threat of glaucoma
occurance in the effected dog. The glaucoma may and may not develop in a dog
with "moderate" degree, in a high age. The risk is relatively low.
However, breeders should be carefully screening the eyes of all their dogs
they want to use in their breeding program, to have evidence, to be able to
follow occurance history and to be able to eliminate the future occurance of
narrow angles, and the risk of glaucoma development, by "breeding away" from
the problem. By carefully selecting breeding pairs and monitoring their
breeding program.
While you can go ahead and breed individuals with
"mild" or "moderate" degree of so called "goniodysgenesis" (which in
translation from the greek medical term meaning "underdevelopment, in our
case we are talking about underdevelopment of the chamber angles in the
eye), we should ALWAYS breed these individuals only to those with a clear
result, which would be on the certificate stated as "without any comments"
or "free of goniodysgenesis".
This way we are talking about "breeding
away" from the problem.
Breeding "mild" to "mild" will produce
"mild", breeding "moderate" to "moderate" will produce "moderate". Dogs with
"severe" degree should not be bred, and in cases of absolute necessity ONLY
to an individual with absolutly clear result.
Briefly: The degree of
the chamber angles do not tell us if a dog has a glaucoma or if the disease
will ever occur. They basically tell us how high or small the risk of the
diesease's occurance in higher age is, as well as how much of a risk of this
disease will the particular dog carry onto his/her offspring.
For
example, if a dog in a mid age (6-8 years old) is gonioscoped with a
"moderate" degree, the risk of him getting glaucoma is quite low, as
generally the angles tend to get more narrow with age. That also makes it a
bit dificult for an opthalmologist to determine if a glaucoma was hereditary
or not, when diagnosing for example a 12 year old dog.
While for
example our dear old Kipp (whom we decided to let go in age 14 due to
blindness caused by progressing severe glaucoma) developed this disease in
high age, and we will never find weather it was genetic or not, it is a good
exmple of why one SHOULD do eye tests on as many dogs as possible. If Kipp's
relatives and acestors were gonioscoped, we would have much more answers for
not only his individual case, but for the future, when breeding on dogs,
somehow related with him.
The tests we so far performed on our dogs,
who come from many different lines, are just a beginning. In one way, we are
fortunate that some of the lines we chose to work with have good feedback
through monitoring the hereditary diseases (not just glaucoma, but also
cataracts, PRA and other) and thus making it a lot more easier for us and
our future breeding progam.
And now think, how much easier it would be
for all breeders, if we all did our share in testing our dogs. The cost is
quite small, comparing to the risks and the suffering of our beloved dogs.
Here in Sweden, the cost for a general eye test (which includes PRA,
cataracts and cornea distrophy testing) is around 400,-SEK.
The
gonioscopy test (for glaucoma) is the same price and it is permanent. That
means that it is performed only once in the dog's life as the result is
permanent.
That isn't so with the so called regular test, as that one
must not be older than 1 year before breeding the dog. The results may
change, as for example cataracts can develop later in the age. Generally,
chosing to breed dogs after they reach certain age also helps to eliminate
the problem as we may not be aware of a disease occurance when breeding the
dog in a young age (for example 2 years old). That is why it is wise to use
older, proven stud dogs, who already have a history of testing behind them,
and most likely several offsprings, some of which had already been tested as
well. The more information about the dog's background you are able to
collect, the better. That's also why, if we have a male at home, it is wise
to wait until a dog's offspring from the first litter are adult and tested
(and here we are not talking necessairly just about eyes, but performance,
temperament, etc.), before we decide to use him again. At least, this is one
of our breeding philosophies in our kennel.
Here is a little
statistics made from the eye tests performed on our dogs so far.
Since
we learned about the importance of eye testing (2003) in siberian huskies,
due to the relatively high risks of hereditary eye disease occurances, we
eye checked 14 dogs so far. One was from our "A" litter, 2 from the "B"
litter, 1 from "E" liter, and one is an offspring to one of the A litter
dogs. Six of these dogs were used in breeding. From these fifteen dogs, 6
were also gonioscoped. NONE of the 15 had any comments on the regular eye
test, 2 had a "mild" degree in the gonioscopy result, 1 "moderate" and 3
without any comments.
There isn't much conclussions to make from this,
these dogs come from different bloodlines and not all were checked for the
same diseases. But yet there is one quite cool thing - We are very happy and
proud to announce, that our very own Sparky (Evening Spark Kipp d'Amundsen)
is the historically very first Kipp d'Amundsen dog, that underwent both of
these tests. And both with a clear result. What is even more important for
us is that Sparky is out of our foundation male Buck (Buck of Geri's Den).
Buck had been tested clear several times already, but today he went for his
gonioscopy test together with his son Sparky, and was also tested clear!
That is a great news for our kennel, as Buck is our true foundation dog, on
whom we are building our line. He had already sired 3 litters for us, out of
which Sparky is the oldest (4 years old now). This gives us a good
background information for the future and we are very, very happy about
being able to build on not just such talented, sweet dog with tremendous
work ethic, good anatomy and excellent breed type, but now also complete
proven eye genetic health. Dr.Hĺkanson commented on Buck's generally clear
eyes and overall fitness and condition. He also thought both Buck and Sparky
have lots of pigmentation in the eyes (a bit more dificult for peforming the
test :), but very good for the "health").
As I said, we are
basically at the beginning, but I would like to incurage all of you, the
siberian husky breeders, to test your dogs as well. It is SO MUCH WORTH IT!
Here are some links you might find useful:
A current list of
veterinary opthalmologists, certified for eye testing in Sweden: here
Common eye diseases in dogs: http://www.acvo.org/public/general.htm
American college of veterinary opthalmologists - official website: www.acvo.org
Hope this piece of information I gathered and experienced, can give you
some feedback and can be of some practical use for you.
And last,
but not least, please remember that eye testing (both, the regular test and
gonioscopy) should be performed in siberian huskies on dogs intended for
breeding, because SIBERIAN HUSKIES DO SUFFER FROM HEREDITARY EYE
DISEASES.
It doesn't matter that some breed clubs do not list
it as obligatory action - it is the breeders' responsibility!
Katerina