For many years, members of the Norwegian Elkhound fancy have known that a small number of our dogs were dying between four months and five years of age of kidney failure. A very similar problem existed in the Shih Tzu, Lhasa Apso, and Soft Coated Wheaten Terrier. It has been referred to as juvenile renal failure or renal cortical hypoplasia.
Is Renal Dysplasia A Current
Problem?
There have been recent reports from the Netherlands, Norway, England, New Zealand
and Australia of groupings of cases in related dogs. These Elkhound owners are
anxious to cooperate with researchers to study this disease in detail. This
includes not only DNA and pedigree analysis but also urine and blood tests,
including glomerular filtration rate (rate kidney filters blood) as well as
kidney biopsy. Researchers at the Veterinary University of Utrecht in the Netherlands
have found depressed GFR in clinically normal dogs related to those with active
disease. It is only through this type of in depth studies that we may be able
to identify sub-clinical cases. Matching the laboratory results with genetic
research should make it easier for researchers to find the answers we need to
get a handle on this condition.
Can Genetic Contributors Be Traced?
The NEAA Health and Research Committee would like to request that anyone who
indicated an incidence of renal dysplasia (15 reported) on the NEAA Health Survey
come forward with a pedigree and medical documentation (confidentiality of
privileged information will be respected). Five pedigrees, dating back as
early as the 1970's, have already been provided, and we need YOUR help
to get this project moving forward. Committee interest in renal dysplasia research
has been discussed with the AKC Canine Health Foundation, and it has been suggested
that a Foundation principal investigator will most likely analyze a minimum
number of pedigrees from Elkhounds with known or suspected renal dysplasia to
determine statistical significance of traceable genetic contributors to JRD.
This is just the first step to establishing a Foundation dialogue with researchers
around the world, especially the Veterinary University of Utrecht.
Are The Genetics Of Renal Dysplasia
Known?
Unfortunately, the exact incidence of renal dysplasia is not known since there
has not been any consistent reporting of this disease. Only when someone that
really cares has a dog die has a flag been raised. When a gene is incompletely
penetrant, a dog can inherit a disease gene, but does not exhibit the disease,
and often passes on the disease gene to its offspring. Genetic theories of JRD
invoke incomplete penetrance and include 1) a mutation in one or two required
genes (one recessive, one dominant), 2) mutation in a dominant gene, or 3) mutation
in a recessive gene. In simple terms, markers are street signs in DNA, and along
each street, like houses, are genes. VetGen has discovered a high probability
of inheritance (linkage) between a DNA marker and the defective gene for juvenile
renal dysplasia (JRD) in the Shih Tzu, Lhasa Apso, and Soft Coated Wheaten Terrier.
The population frequency of the alleles (two copies of a gene, one inherited
from each parent) of the linked marker in the three breeds is about 30%. In
very simple terms, breeding away from the DNA marker significantly reduces the
risk of JRD in puppies you produce.
What Are The Symptoms Of Affected
Dogs?
The first clinical symptom of affected dogs is usually an increase in urine
output and accompanying thirst. When checked, the urine is extremely dilute,
often approaching the specific gravity of water, which is 1.000. The normal
range for a dog is between 1.015 and 1.045. In most dogs anything consistently
below 1.015 would be called low and suggestive of kidney disease. Breeders certainly
should consider adding urinalysis as a prerequisite for breeding to rule out
early clinical cases. Later in the disease the dog may exhibit loss of appetite,
muscular weakness, vomiting, diarrhea and foul breath. The clinical symptoms
can often be reduced initially by using prescription low protein diets. Unfortunately,
this works for only a limited amount of time as the deterioration of kidney
function continues, ultimately leading to the demise of the dog. Early diagnosis
would necessitate blood and urine tests as well as GFR studies and biopsies,
if the GFR were low. In dogs with renal dysplasia there should be no glucose
to implicate diabetes or elevated protein to suggest protein-loosing disease.
Certainly a blood panel at the same time would help to eliminate other diseases,
too.
Dominant anomalies are seen and culled. Recessive anomalies are the problem as carriers are hard to identify. A DNA marker for the defective gene for juvenile renal dysplasia (JRD) in the Elkhound would help reduce the incidence of renal dysplasia. It is obvious that this problem affects all of us concerned about this breed. It certainly would be prudent for all Elkhound owners in the United States to share in the research efforts, as we will certainly benefit from it. All past and current cases should be reported and studied, along with closely related sub-clinical dogs. Watch the NEAA web site (www.neaa.com) for further information on this study.
If you wish to submit a pedigree of a dog (past or present) affected with renal dysplasia, send your pedigree to:
Daniel R. Lawer, DVM
NEAA Canine Health and Research Committee
5447 Diablo Drive
Sacramento, CA 95842
E-mail: DRLawer@aol.com
© June 2000, all rights reserved, NEAA Canine Health and Research Committee
Permission to reproduce and distribute this document is granted by the author and the Norwegian Elkhound Association of America, Inc. Original written material may be reprinted provided due credit is given. Articles are printed over the signature of the author and are not necessarily the opinion of the Norwegian Elkhound Association of America, Inc.
© NEAA 1998-2005. All rights reserved.
All content on this website is protected under US Copyright Law and rights
belong to its owner. No content, including photos, graphics, text, or
other content
or intellectual property may be reproduced without prior written permission of
its owner.
Revised: November 26, 2003
Contact NEAA for more information.
This web site is
maintained by Highland Web Design