A to Z Index
Susan L Fleisher, email@example.com or firstname.lastname@example.org
Copyright 1996, all rights reserved.
I. Definition and Description
Juvenile renal disease (JRD) and other congenital or familial forms
of renal dysplasia are seen in about twenty breeds of dogs.
According to Kenneth Bovee, DVM, (Professor of Medicine at the
University of Pennsylvania), the clinical entity has considerable
variation from breed to breed and has completely different
prevalence rates. A table which lists all of the congenital and
familial renal diseases of dogs by breed can be found in Veterinary
Pediatrics Dogs & Cats from Birth to Six Months. (1)
In affected standard poodles, histological findings include "cystic
glomerular atrophy and large numbers of immature ("fetal") glomeruli
are observed, especially in dogs at 3 to 4 months of age. Secondary
tubular changes consist of focal to diffuse tubular dilatation and
atrophy as well as basement membrane mineralization. The cortical
interstitium contains segmental areas of fibrosis, whereas more
diffuse lesions occur in the medulla. Interstitial infiltrates of
mononuclear cells are minimal in younger dogs and more severe in
older dogs." (2) "Hypoplastic kidneys appear as miniature replicas
of normal kidneys composed of reduced numbers of histologically
normal nephrons". (1)
There are a number of hereditary nephropathies that cause renal
failure in young dogs. The genetic nature of these diseases makes
accurate diagnosis imperative so that affected animals are not bred.
Usually, in standard poodles the disease is discovered before
breeding age, but diagnosing a puppy affected with JRD could prevent
both the sire and dam from being bred again.
In standard poodles with JRD, symptoms can be noted as early as a
few weeks after birth; and affected puppies are almost without
exception symptomatic before two years of age. Some puppies are seen
because of a failure to thrive: most grow normally until symptoms
appear. Puppies with renal dysplasia may appear clinically normal
for extended periods of time before developing signs of chronic
renal failure. The rate at which renal dysplasia progresses to overt
renal failure depends on the severity of initial renal lesions and
factors resulting in progressive loss of renal functional mass. (1)
Larry Cowgill, DVM, (University of California, Davis), told me that
many puppies born with renal dysplasia do better than dogs who
acquire kidney disease later in life. He said that these puppies are
able to plateau until a small insult occurs, and then they
Early symptoms of juvenile renal disease include polydipsia,
polyuria, and dilute urine which has little color or odor. Some
affected puppies leak urine, many do not. Often a puppy owner's
earliest complaint is about the difficulty of housebreaking a puppy
later discovered to have JRD. The volume of water consumed, and, in
some puppies, leakage of urine can make housebreaking a formidable
task. As the disease progresses, vomiting, weight loss, anorexia,
lethargy, and muscle weakness are seen. There is sometimes a
chemical odor to the breath as a result of metabolic waste not being
excreted by the kidneys.
If the reduction in renal function is identified early, when only
polydipsia and polyuria are evident, medical management can be
instituted immediately. Although the renal damage is not reversible,
the quality and length of the patient's life may be improved by
early treatment. (3)
Blood urea nitrogen (BUN) and creatinine are the two most commonly
utilized measurements of renal function, with creatinine being the
more accurate measurement. They are approximations of the glomerular
filtration rate (GFR), and when the GFR is reduced to 25% of its
normal rate, they become elevated above the accepted reference
ranges . BUN and creatinine test for renal failure and will not
indicate renal disease prior to failure. BUN and creatinine values
begin to rise slightly as renal function is lost, but do not exceed
the reference range until only 25% of renal function remains.
Although a BUN can be elevated by non renal causes, BUN values
seldom exceed 50mg/dl as a result of non-renal causes. If the
elevation is not the result of primary renal failure, then the
patient should be able to concentrate his/her urine to a specific
gravity (SG) above 1.030, except in instances of renal medullary
washout. The inability to concentrate urine occurs when two thirds
of the renal function is lost. (3)
Serum phosphorus levels are often not elevated in cases of juvenile
renal disease. Where the reduction in renal function progresses
slowly, the puppy compensates and the serum phosphorus levels can
remain normal. About 75% of renal function must be lost before this
elevation is detectable. (3) In the cases I have followed, although
BUN and creatinine levels were often greatly elevated, serum
phosphorus levels were increased in only about 50% of cases.
If a standard poodle under two years of age is found to have an
elevated BUN and creatinine and significant proteinuria, as
indicated by an increased urine protein:creatinine ratio, JRD should
be strongly suspected. Abdominal palpation may reveal small
irregularly shaped kidneys. An ultrasound can be a useful diagnostic
tool, since the kidneys are usually atrophied and underdeveloped. It
must be kept in mind, however, that kidneys from affected dogs may
be normal size.
The most accurate method for diagnosing JRD is a wedge biopsy from
one kidney taken any time after the second month of life, or a
histopathologic exam at necropsy. The histopathology of these
puppies should be examined by an experienced pathologist. There are
a number of pathologists who have a considerable interest in this
disease. (4) A biopsy or autopsy of a puppy less than 2 months of
age would not be fruitful, since the normally immature kidneys could
not be distinguished from those affected by JRD. It would not be
reasonable to expect the owner of a JRD puppy to consent to a wedge
biopsy, since the findings would not change the treatment or
prognosis of the disease.
Treatments for the symptoms of JRD include a low protein
prescription diet, such as Hill's K/D. The predominant effect of the
low protein diet is to minimize production of uremic toxins so that
the patient feels better. Low protein diets may help extend life in
dogs. Phosphorus is more important in this regard, since high
phosphorus accelerates renal failure, and restricted phosphorus
slows it down. K/D is low in phosphorus, so it remains a good food
for dogs in this condition. Low phosphorus diets allow management of
secondary hyperparathyroidism by restricting phosphorus intake and
reducing phosphorus absorption from the gastrointestinal tract.( 5,
6) In addition to diet, IV fluids can be administered to correct
disturbances created by the retention of uremic toxins,
extracellular fluid volume, hyperkalemia, and acid-base imbalances.
Epogen can be prescribed to treat the hypoproliferative anemia of
chronic renal failure, resulting in improving the quality, and
probably the length of life. Some veterinary schools are performing
organ transplants, but transplanted kidneys in dogs are commonly
rejected, and involve an extraordinary expense and commitment.
These treatments are palliative at best, and the prognosis for JRD
is grim. Puppies usually die within several months of being
diagnosed, almost always before age two I am, however, following the
progress of two dogs who have JRD with what appears to be less
severe kidney involvement, and who are being well maintained on low
protein and low phosphorus diets. These dogs are now both more than
three years old, and both were diagnosed before they were
symptomatic. One was tested because five of his littermates died of
JRD, and one because his veterinarian was giving free BUN tests to
her clients along with heartworm checks. These two dogs are an
exception in my experience with JRD in this breed. Although they are
doing well, ultrasound has revealed that their renal disease is
bilateral. Unilateral renal dysplasia may be clinically silent, and
the dog may live a fairly normal lifetime.
Because no effective treatment for JRD exists, the most promising
approach for dealing with it is for clinical veterinarians, owners
and breeders to understand its genetic basis. Veterinarians can play
an important role in research by being aware of genetic diseases in
specific breeds, of ongoing research in these genetic diseases in
specific breeds, and by directing breeders and owners of dogs
affected by these diseases to the people researching them. Every
puppy who comes to our attention, adds to the JRD data in our
research database. If the mode of inheritance can be determined
using litter data from puppies already born, it may not be necessary
to breed test litters, or it may be possible to breed fewer test
II Background of my involvement
In January of 1990, I had my 21 month old standard poodle puppy put
down. She was one of three puppies in a litter of 11 to die of JRD.
All three of the puppies with the disease appeared healthy and grew
normally until clinical signs appeared at 10 months in one, and at
20 months in the other two. The disease is devastating. Nobody
expects to lose a puppy of that age. As a first time dog owner, I
was not aware that her prodigious water consumption was abnormal, or
that her urine, which had very little color or odor was evidence of
pathology. Veterinarians who ask questions of new pet owners to
elicit information about water consumption and the concentration of
urine increase a client's awareness of these variables.
After her death, I began searching the literature to discover what
was known about JRD in standard poodles, including what, if any,
research was being done in order to establish the mode of
inheritance of this disease in this breed. After finding that no one
was working on this problem, I began a collaboration with George
Padgett, DVM, geneticist and Professor of Pathology at Michigan
State University. Our objective is to establish the mode of
inheritance of JRD in standard poodles, and an eventual open
registry at the Institute for Genetic Disease Control in Animals (GDC),
in Davis, California. Using an open registry, breeders who wish to
can reduce the incidence of this disease, if not breed it out
III What is known about the genetic basis of JRD
Dr. Padgett told me that in most of the breeds in which JRD has been
studied, it is a simple (one gene), autosomal (not sex linked),
recessive (both parents have to carry the gene) disease. The
presence of just one affected puppy determines that both parents are
carriers. Littermates of an affected puppy have a 67% chance of
being carriers. Aunts, uncles, and grandparents of an affected puppy
have a 50% chance of being carriers.
A sire who has produced an affected puppy is a defined carrier. If
the same sire has been bred to bitches who produced sizable litters
with no affected puppies, those bitches have proven themselves to be
probably clear. This is referred to as Retrospective Test Mating.
"Proven" is used rather loosely here, since statistically a dog
mated to a carrier and producing six normal offspring would still
have a 17.8% chance of being a carrier. Twelve normal offspring
would reduce that chance to 3.17%. The preceding figures which refer
to simple autosomal recessive anomalies are from Malcolm B. Willis's
book, Genetics of The Dog. (7) Even if only the sire or dam of a
litter is a carrier, the other parent being clear, an average of 50%
of all their puppies are carriers themselves.
I have been tracking a large number of affected litters, and the
number of JRD puppies within them. Dr. Padgett informed me in March,
1996, that using the Chi-square statistical test on the data I have
collected, the data is consistent with JRD in standard poodles being
a simple autosomal recessive disease at the 97.5% level of
significance. (6) It is possible that as more data is collected, the
conclusion about the specific mode of inheritance may change.
Dr. Padgett noted that with perhaps as few as six additional
accurately diagnosed litters which are already in existence or with
one or two test matings of proven carriers, the data will become
sufficiently robust to be publishable in any of a number of
scientific journals. (8)
IV What clinical veterinarians can do to help
In order for JRD to be further studied in standard poodles several
things have to occur. Veterinarians need to become aware that JRD is
a problem in this breed. Clients with affected puppies should be
informed that this disease is genetic, and should be encouraged to
inform the breeder and the owner of the sire of the puppy's illness.
If the puppy is determined to have JRD, the rest of the litter can
Most individual cases of JRD are treated by owners and veterinarians
as isolated occurrences rather than as the manifestation of a
genetic disease. Often breeders are not informed about a medical
problem in a puppy they have sold. When owners do inform breeders,
it is usually just the owner of the dam who is contacted. Unless
there are multiples in a litter, it goes largely unrecognized, and
no thought is given to those littermates who are carriers.
When a puppy suspected of having JRD is diagnosed, or dies, the
client should be referred to researchers by the veterinarian
involved in his/her care. If that does not occur, the affected puppy
will have died without it's death having contributed to the valuable
fund of information. In these cases, the puppy and the entire litter
is wasted and lost to us for research purposes. Unless veterinarians
are aware of the ongoing research and the need for referral of these
puppies, we will not be successful in obtaining the data that is
necessary to understand JRD.
Veterinarians can also encourage owners to have limited autopsies
performed, so that the kidney tissue can be examined under a
microscope. If the cost of a limited autopsy to examine the kidneys
is a great financial burden for a client, it is possible that we
could find some financial assistance.
The mode of inheritance of JRD can be established from information
about the number of puppies born in a large number of affected
litters and the number of puppies in those litters who are affected
by JRD. In addition to the litter data, obtainable from the owner
and breeder, we need data from the veterinarian to confirm the
diagnosis of JRD. Lab reports, ultrasound reports, biopsy results
and autopsy reports are all useful.
Several of the most heavily used standard poodle sires have been
carriers of JRD, and there is a high probability that a veterinarian
with standard poodle breeders or owners among his/her clients, will
encounter this disease.
V Ongoing Research
The Department of Human Genetics at Michigan State University has a
large grant to be used in gene marker research on dogs. The initial
effort will be to develop 400 DNA probes in order to saturate the
dogs' chromosomes with the probes. After the probes have been
established, screening can begin for linkage of any dog disease gene
of interest. Eventually, the benefits will be that dogs will be able
to be screened for the carrier state of the gene. This research will
not be completed for many years.
In order to carry out screening for linkage for this or any other
genetic disease, pedigrees of 15-20 litters in which there are at
least two affected and two unaffected puppies must be identified.
Cheek swabs (buckle smears) >from at least two affected puppies and
two unaffected puppies in each litter, as well as from both parents
have to be made available for study. Puppies >from a repeat breeding
are considered littermates for this purpose.
Several other universities, Texas A & M, and the University of
California at Berkeley (The Dog Genome Project) with the University
of Oregon, are involved in canine DNA research, as is Cornell
University. If the mode of inheritance of a disease is known,
screening for the DNA marker(s) becomes easier and less expensive.
George Lees, DVM, Professor of Medicine at Texas A & M University,
has a grant to study JRD in English cocker spaniels. The JRD in
cockers is a form of hereditary nephritis, and is not the same
disease as that seen in standard poodles. He and his researchers are
using electron microscopy, and intend to search for the genetic
basis of that disease in English cocker spaniels when more funds
become available. Their research will include other breeds as well,
but they are only investigating hereditary nephritis. (9)
Waiting for DNA testing to become readily available is not a
feasible solution to the problems of genetic diseases. Selectively
breeding away from carriers now is the only responsible action.
Registries for many canine diseases are being established at the The
Institute for Genetic Disease Control In Animals. (10) Clearly, an
open registry such as the one established at the GDC in July, l992,
for sebaceous adenitis in standard poodles (this disease also occurs
in about 30 breeds) is an important step forward and an invaluable
resource. In Europe, open registries have made it possible for
breeders to greatly reduce the number of cases of some genetic
I have collected pedigrees of 75 litters of an American Champion
sire. There are a large number of Champions among his offspring. In
at least two of these litters there was one puppy with JRD. The sire
is therefore a carrier, and, on average, half of the puppies in
every one of his litters are carriers. The possibility that JRD will
touch every standard poodle breeder eventually is likely. By the
time it does, it will be difficult if not impossible to eliminate
from the breed.
VI Prior Research
Several articles on JRD and familial renal disease were published in
veterinary journals in the 1970s, and others have been published
since that time on juvenile or familial renal diseases in doberman
pinschers, Alaskan malamutes, Norwegian elkhounds, bull terriers,
Airedale terriers, bedlington terriers, boxers, King Charles
spaniels, keeshunden, Yorkshire terriers, Newfoundlands, and
samoyeds. (1) These diseases have also been reported in rottweilers,
chow chows, miniature schnauzers, shih tzus, Lhasa apsos, soft
coated wheaten terriers, Portuguese water dogs, Chinese shar- peis,
and cocker spaniels, among others. (2,11 ) There was a recent report
in the Veterinary News section of the AKC Gazette, that it is being
seen in golden retrievers, as well, a breed in which it had not
before been recognized. An article written by Stephen DiBartola, et
al., JRD in related standard poodles, appeared in JAVMA in
September, 1983, and provides references to the literature prior to
that date. (12) Dr. DiBartola also lists more recent references in
his chapter, Familial Renal disease in Dogs and Cats, Textbook of
Veterinary Internal Medicine. (2)
Acknowledgements: I thank the following people for their generosity
and time in providing me with a greater understanding of this
disease, in conversation, in letters, and on-line: Kenneth Bovee,
DVM, University of Pennsylvania; George Brewer, MD, University of
Michigan; Larry Cowgill, DVM, University of California, Davis;
Stephen P. DiBartola DVM, Ohio State University; George Lees, DVM,
Texas A & M University; Barbara Licht, PhD, Florida State
University, Tallahassee; George Padgett, DVM, Michigan State
University; Dianne Sequoia, DVM, Berkeley, California; Sue
Tornquist, DVM, Washington State University; and the wonderful
veterinarians onVETMED-L. Any errors are my own, and not those of
the veterinarians with whom I spoke or corresponded.
I can be reached at:
fax 419 735-5818
phone 510 527-0793
2112 Eunice Street, Berkeley, CA 94709-1417
(c) Copywrite 1996. This article may be reprinted without permission
only in its entirety. I would appreciate being sent a copy of any
publication in which it appears.
A "Problem Specific Data Base for Renal Failure in Immature Dogs" is
included in the chapter on renal disease in Veterinary Pediatrics,
Dogs & Cats from Birth to Six Months, 2nd edition, as is a table on
"Medical Management of Chronic Renal Failure". (1)
1. Kruger, J.M., Osborne, C.A., et al. : Congenital and Hereditary
Disorders of the Kidney. Veterinary Pediatrics Dogs & Cats from
Birth to Six Months., 2nd edition. (J.D. Hoskins, ed.) W.B.Saunders,
Philadelphia, Pa, 1995: pp 401-406.
2. DiBartola Stephen P. et al: Familial Renal disease in Dogs and
Cats. Textbook of Veterinary Internal Medicine. (S.J. Ettinger, &
E.C. Feldman, ed) W.B. Saunders, Philadelphia, Pa. 1995:pp
3. McMaw, D.l; Fleming, E.J.; Mikiciuk, M.G. : Chronic renal failure
in dogs: Managing an irreversible condition. Symposium on Renal
disease. Veterinary Medicine; March 1989; p 297-303.
4. Kenneth Bovee, DVM (University of Pennsylvania); Stephen
DiBartola, DVM (Ohio State University); and George Padgett, DVM
(Michigan State University may be contacted for referrals.
5.. Polzin, D.J.; Osborne, C.A.: Update - Conservative Medical
Management of Chronic Renal Failure. Current Therapy IX (R.W. Kirk,
ed.) W. B. Saunders, Philadelphia, PA., 1986 pp 1167-1173.
6. Finco, D.R.: The Role of Phosphorus Restriction in the Management
of Chronic Renal Failure of the Dog and Cat; Proc. 7th Kal Kan Sypm.
. Veterinary Learning Systems, Lawrenceville, NJ 1983; pp 131-133
7. Willis, Malcolm B: Genetics of the Dog. Howell Book House, New
York, NY, 1989;p 356.
8. Poodle Variety, Santa Barbara, CA, February-March 1996, pp 88-89.
9. personal correspondence September 5,1995.
10. GDC, P.O. Box 222, Davis CA 95617. telephone or fax 916 756-6773
11. Crawford, M.A.:The Kidneys, Congenital and Inherited
Disorders.Veterinary Pediatrics Dogs & Cats from Birth to Six
Months. (J.D. Hoskins, ed.) W.B. Saunders, Philadelphia, Pa, 1990:
12. DiBartola S.P., Chew D.J., et al: Juvenile Renal Disease in
related Standard Poodles. JAVMA:183:693-696.
Bovee, K.C.: Overview of the Uremic Syndrome. Current Veterinary
Therapy VII (R.W. Kirk, ed.) W.B. Saunders. Philadelphia, Pa., 1980.
Chew, D.J.; DiBartola, S.P.: Manual of Small Animal Nephrology and
Urology. Churchill Livingston. New York, NY. 1986; pp 1-78.
Krawiec, D.R.: Renal Failure in Immature Dogs. JAAHA 23:101-107;
McMaw, D.l; Fleming, E.J.; Mikiciuk, M.G.. : Selecting the right
diagnostic tests for renal disease. Symposium on Renal disease.
Veterinary Medicine; March 1989; pp 267-272.
McMaw, D.l; Fleming, E.J.; Mikiciuk, M.G. : Interpreting the results
of urinalysis: A key to diagnosing renal disorders. Symposium on
Renal Disease.Veterinary Medicine; March 1989; p 281-286.
Picut, G.A.; Lewis. R.M.: Comparative Pathology of Canine Hereditary
Neuropathies: An Interpretive Review. Vet. Res. Comm. 11:561-581;
Picut, G.A.; Lewis, R.M.: Microscopic Features of Canine Dysplasia.
Vet. Path. 24:158-163; 1987.
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