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Breeders of Bull Terriers come and go and new ones enter the
breed so for all you new breeders welcome and here’s
something to take on board in your quest for the best of the
best. As for the rest of us. Maybe a quick refresher on
the subject? And maybe it is time seven years after the
article was written for all our breed clubs to push for
research.
Appeared in the N. E Bull terrier club magazine 2004
INHERITED KIDNEY DISEASE IN BULL TERRIERS
By Dr.
Caroline O’Leary
University of Queensland
Inherited Kidney disease (IKD)
has been reported in many breeds of dog including the Bull
Terrier and Miniature Bullterrier as well as in people.
There are many different
types of kidney disease, inherited (or genetic) faults being
only one cause. Infections, poisons, some drugs,
non-genetic cancers, liver, pancreas, uterine, heart disease
or many other diseases can cause kidney disease.
The inherited condition in
Bull Terriers can occur in very young (less than six months)
middle aged or very old animals. Some dogs can be ten years
plus and have the faulty gene in their make-up, pass it on
to some of their pups, and may appear normal to their
owners. These animals may live to a ripe old age with
no-one suspecting they have the disease.
Signs of kidney failure that
are common to both types of IKD and to other causes of
kidney failure include the following.
-
poor appetite- dullness
or lethargy-weight loss or stunted growth-poor hair ¾
coat- vomiting/diarrhoea-foul breath and mouth
ulcers-muscle twitching and convulsions-drinking excess
water and passing too much urine-owners often notice an
increase in the urine passed overnight-pale gums
(anaemia)-dehydration (sticky gums).
There are two types of IKD
in Bull Terriers.
The first type of IKD is
polycystic kidneys where the kidneys contain
fluid filled cysts (or balls of fluid) which can be seen by
looking at the kidney, for example by using an ultrasound
machine, where they may be seen as ‘black holes’ inside the
kidneys. At what age this is commonly detectable is not
known. While it is possible to detect the defect in some
dogs as puppies, it may be that in some animals it is not
obvious until the dog is much older. In this disease a
urine test will not pick all affected dogs, so an ultrasound
is ideal.
The second condition is
nephritis where the kidneys may look fairly
normal until a biopsy (or small piece of tissue taken from a
live animal) is examined under a microscope. It is not
possible to diagnose this disease on the basis of an
ultrasound examination. A urine test, or kidney biopsy are
the best tests for this disease.
Both conditions are thought
to be inherited in an autosomal dominant fashion, which
means that only one parent has to have the fault for half of
the litter to be affected. If both parents have the fault ¾
or more of the pups may be affected.
Because of the way these
conditions are inherited, there is no point in condemning
whole kennels or bloodlines. As an affected dog may produce
unaffected puppies and these animals do not have the
faulty gene/s, these animals are fine to be bred with as
long as they are regularly tested. They have the virtues
present in the line without the ‘taint’
Of the faulty gene/s.
Dogs that have either of
these inherited problems SHOULD NOT be bred from.
There is no test available
that can say for sure that dogs are unaffected below one
year of age. It is possible some affected dogs are not
detected until they are 3 or 4 years old.
Even leaving the ethical
problems out of deliberately breeding affected dogs that
must be euthanised or given to homes with the knowledge that
they are affected by a deadly genetic disease, these dogs
cannot be reliably cleared until they are at least 1 year
old and possibly 3-4years old.
These dogs would have to be
kept until this age before being bred.
Dogs affected by both these
conditions may have bloody urine on and off, and the vast
majority of dogs with nephritis and some dogs with
polycystic kidneys will have abnormal levels of protein in
their urine (this is shown with a UP/C or urine protein to
creatinine ratio). Only a few who are late in the course of
the disease will have abnormal blood results. In both these
conditions, how fast the disease progresses and how severe
it is varies from dog to dog..
The Urine Protein to
Creatinine ratio (UP/C) is a very sensitive test and is
valuable in detecting nephritis and some polycystic kidney
disease before signs of kidney failure appear (so
lengthening the dog’s good quality of life) and hopefully
before the dog is bred. Using this test will hugely decrease
the nephritis problem within one generation. This is
especially so as it is possible to prevent popular
affected stud dogs spreading the faulty gene/s widely
by detecting them much earlier than was possible before with
the BUN test.
Animals with a high UP/C
need to have a full urinalysis completed to rule out other
causes than inherited kidney disease. If the UP/C is high
and thee are no other obvious causes (eg reproductive
problems, bladder problems) an ultrasound examination and
possibly a kidney biopsy will give the full answer.
The UP/C test is easy to
use and relatively cheap, making it an ideal screening test
for nephritis. We believe most of the affected bull
terriers have a high UP/C result by the time they are 1 year
old. There are possibly occasional dogs that are affected,
that only have a high UP/C once they are 3 or 4 years old,
but there are no published records of this. (at the time
of going to press) Life long retesting is recommended at
this stage.
A lot of hard work needs
to be done to investigate both diseases. The relationship
between these two diseases needs to be looked at, the value
of current testing procedures needs to be continually
monitored and, hopefully in the future a genetic test will
be developed that can be done once in young pups to predict
which ones have the faulty gene/s.
There is no effective cure
for either condition. Prevention by breeding dogs free
of these inherited faults is the best solution.
At this stage palliative
treatment to maintain comfortable life for as long as
possible is the usual treatment for IKF.
If the kidney failure is
recognised early in its course the following can be tried;
-
Constant access to fresh
water- controlled protein, phosphorous and salt diet(
use only with care in growing dogs)- phosphate binders
to bind phosphorous in the diet- water soluble vitamins
(especially B vitamins)- hormones for anaemia-
medication for nausea and stomach ulcers- blood pressure
medication if necessary. Some of the reason so little
is known about inherited diseases include;
-
Hard to detect carriers
of faulty genes cheaply, accurately and early in the
life before dogs are sold or used for breeding-
differences between dogs in the way the disease appears-need
for comment from the Breed Clubs to support research
into the problem and develop strategies to breed soundly
-
A certificate system
to encourage breeding from unaffected dogs and a
national register appears to be the best solution
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