QUICK INDEX: Introduction,
Goal of the Effort , Scope of the Effort , Description of the problem , Technical
Obstacles , The Human Component , An Approach to the Problem , Basic Education,
Genetic Information Sharing , Preregistration Testing , Show Validation ,
Modification of Breed Standards , Registration Organizations , Health Related
Organizations , Conclusion , Selected References ,
Introduction
This paper is the first product of an effort I have undertaken that was
prompted by the discovery that our five month old Scottish Terrier suffered
from Type III von Willebrand's Disease (vWD). The existence of this genetic
bleeding disorder was unknown to us until he suffered a near fatal bleeding
episode for no apparent reason. Subsequent treatment and testing revealed
that he was affected with vWD.
We were quite naive - as I suspect many people are - when we bought our
dog. Both of his parents were AKC registered, which we assumed meant that
he was a healthy dog from healthy stock. In fact, prior to discovering his
affliction, he too was registered (though we could have registered him even
after discovering his malady). We have learned the hard way that "having
papers" means very little, if anything, about the genetic health of a purebred
dog.
This experience convinced us that dogs, and those who own them, should not
have to live under the conditions dictated by genetic diseases. This is especially
true since in the main they could be prevented. Our dog's disease has generated
a lot of additional expense and worry which might have been avoided by a properly
designed and managed breeding program. It has also become clear to us that
prospective buyers should be better educated about the world of dogs before
they make an investment that could lead to considerable extra expense, and
worse, the heartbreak of losing a beloved friend too early.
This effort has no funding or sponsorship from any organization or other
individuals. We neither breed nor show dogs, and have no plans to do so in
the future. This is a personal attempt to contribute to the identification
of, the development of tests for, and the progress of efforts toward the eradication
of genetic diseases in dogs.
This article is intended to be an objective exposition on the subject of
genetic diseases in domestic dogs. It is of the utmost importance that the
information presented be as neutral as possible so as to encourage all interested
parties to engage in productive dialog. No attempt will be made to attach
any measure of goodness or acceptability to one view of an issue over another.
It is hoped that this approach will enable synergies to be created by joint
activity among and between parties interested in improving canine genetic
health.
While no one is intentionally being eliminated from the target audience,
the specific constituencies being addressed are breeders, breed clubs, dog
registration organizations, prospective dog purchasers, researchers, and veterinarians.
Goal of the Effort
The goal of this effort is to provide assistance to any and all concerned
parties in hopes of making progress toward the elimination of genetic diseases
in dogs, and to generate additional interest in that effort. To that end,
it is intended to:
Educate the audience on the subject of genetic diseases in dogs. Present
a brief summary of some of the research and other activities currently underway
which are working toward the elimination of genetic diseases in dogs. Suggest
some options and approaches which can be examined with regard to their effectiveness
in reaching this goal, in both the short term and the long term. Foster open
dialog and cooperation among and between all interested parties.
Scope of the Effort
Although primarily terrier breeds are referenced here, this effort is not
limited to any specific diseases or breeds. On the contrary, it is intended
to encompass the widest range of both. It is hoped that in this way, the largest
possible group of people will be induced to participate, and the broadest
view of the subject will be developed.
This document is a first step, and proposes to use Type III von Willebrand's
Disease in the Scottish Terrier as the example around which to build a framework
for further efforts. The current level of knowledge about this disease is
extensive, and indicates that this disease, in this breed, presents one of
the simplest cases of genetic disease in the dog. Even if this proves to be
true, vWD still offers a formidable set of challenges to the community committed
to its eradication. But as a relatively simple example, it provides the opportunity
to"start small". The framework developed for attacking vWD could be used
as the starting point for more elaborate requirements which would be dictated
by more complex diseases.
Description of the problem
Many diseases in the domestic dog are genetic in origin. Examples are vWD,
Collie Eye Anomaly, portosystemic shunt, hemophilia, Scottie Cramp, hip dysplasia,
Legg/Calv Perthes, medial patellar luxation, and craniomandibular osteopathy
(CMO) -- the list is very long. So far, over five hundred genetic diseases
have been identified in purebred dogs, and over a hundred in mixed breeds.
They can affect conformation, health (virtually all systems in the body are
subject), and temperament. In Scotties alone there are 36 identified genetic
diseases, with similar numbers affecting each of several other terrier breeds.
There is a great deal of scientific research being performed on the identification
of the specific causes of genetic diseases. Because some of the diseases exhibited
by dogs are also evident in humans -- vWD is the most common human inherited
blood disease -- some benefit could derive from canine research which would
be of use in pursuing the human form of the same, or related, diseases.
Technical Obstacles
"There are no more easy problems." Anonymous
The need for accurate definition of the mode of inheritance - The underlying
causes of genetic diseases can be very complex. Efforts are underway to identify
and isolate specific genes, and combinations of genes, related to various
diseases. But it will probably be a very long time before most have been isolated.
The research process is costly and very time consuming.
Variation in the expression of the disease - Genetic diseases which appear
to be identical across breeds may in fact be caused by different genetic conditions.
For example, vWD is believed to exemplify one mode of inheritance in Scottish
Terriers, and another in German Shorthaired Pointers.
The absence of accurate tests - Some genetic characteristics can be determined
by observation, but more frequently tests are necessary to identify specific
genetic diseases. There are currently two tests for vWD, one more recent (and
accurate) than the other. They test for the same constituent in the blood,
but use different testing techniques. These tests are based upon measuring
the quantity of a specific chemical in the blood, and while the test itself
is very good, the results are subject to substantial variation based upon
the collection and handling of the test samples. And there can be major variations
in the amount of the chemical present in the animal due to its condition at
the time of sample collection. Other genetic diseases depend upon other methods
for their diagnosis. These include X-ray, physical manipulation, and other
techniques. Testing for recognized genetic markers, or the genes themselves,
will offer a virtually foolproof method for diagnosis. When a definitive
test is developed for any disease, there should be no reason to ever produce
a puppy adversely affected by that disease.
The Human Component
Any attempt to address the genetic disease problem in dogs must take into
account the human component. People breed dogs for many reasons. While there
are exceptions to every rule, most breeders of pedigreed dogs do seem to have
the animals' best interests at heart. In the main, the production of dogs
with genetic diseases today is not done out of malice, but out of ignorance
due to a of lack of historical genetic information.
But there are other forces at work as well. Many dogs are shown at events
sanctioned by various registration groups. Breeders of winning dogs earn the
respect of their peers and others, and that respect can lead to enhanced benefits
to the breeders. Within this environment, other benefits can also be accrued
from breeding winning dogs. These include improving the breed; gaining personal
satisfaction; and commanding higher prices for puppies bred from the winner's
bloodlines.
For genetic diseases to be eliminated, they should be given at least as
much weight as the other factors considered when breeding a dog -- principally
conformation and behavioral traits. For any plan to be successful would probably
require that these benefits remain achievable at current rates or better.
The incentives provided for the breeding of dogs without genetic diseases
should be at least as good -- probably better -- than exist today.
An Approach to the Problem
Since genetic diseases are passed to subsequent generations by parents who
contribute the causal factors contained within their own genetic makeup, one
point regarding this problem is fundamental:
The elimination of genetic diseases can only be accomplished through selective
breeding
The problems lie in determining how to identify the diseases' causal factors
in dogs; in understanding when not to breed them; and in the implementation
of selective breeding programs based upon these factors. Some of the avenues
to be investigated include:
Basic Education
First and foremost in solving any problem is ensuring that everyone involved
understands it. While genetics can be a very complex technical subject, the
basic information required to make progress toward the elimination of genetic
disease by developing an effective breeding program is within the reach and
understanding of everyone concerned.
Breeders should understand the implications of genetic diseases recognized
as affecting their breeds, and take steps to breed only those dogs that will
minimize the propagation of unwanted characteristics.
Prospective buyers should be made aware of the genetic diseases related
to the breed they are considering. And they should learn to ask that test
results or genetic histories for the animals they are planning to purchase
be explained to them.
Veterinarians should be able to recognize genetic diseases, and inform owners,
breeders, and prospective breeders of their presence in dogs they examine
and treat.
A general information publication on genetic diseases in all dogs could
be prepared. A cooperative effort among many breed clubs and other interested
organizations could reduce cost and gain maximum exposure for such a product.
By crossing many breeds, a single publication could be offered to the public
at many venues, including shows for single and multiple breeds, county and
state fairs, and other events at which those interested in dogs might be expected
to attend. There are many opportunities to spread the word.
Genetic Information Sharing
Dog breeders should have access to at least the phenotypic history of dogs
in the lines that produced the prospective mates. Having this information
would help breeders to reduce the probability of the occurrence of diseases
by enabling them to determine the statistical risks involved for propagating
those diseases. The absence of this information means breeding with no possible
way of predicting the outcome. It becomes a matter of pure chance.
One way to make this essential information available to breeders is through
an open registry, in which genetic diseases are recorded along with the information
currently available in the pedigree. Today a stigma is often attached to a
breeder and their breeding stock if this information is made known. Rather
than sharing the information, this attitude leads to hiding it away. Open
registries sponsored by breed clubs could remove this obstacle, and facilitate
improved breeding programs. While not perfect, it can certainly help to reduce
the problem, and it is within the reach and capabilities of everyone today.
Preregistration Testing
Testing of animals could be required before they are accepted by registration
organizations. Ideally, registration would automatically enhance the database
of genetic information available for use in breeding programs. Very few registration
organizations do this today. Registration of litters could be withheld until
test results, histories of the parents, or both were presented to and validated
by the organizations. Registration could also carry with it the requirement
to monitor the ongoing health of the dog, and to report the appearance of
genetic diseases should they occur after registration.
Show Validation
Participation in shows could be made dependent upon test results being furnished
to, and being evaluated by, the sponsoring organizations. Once entered, judges
could impose penalties on animals that were found to have visible characteristics
related to genetic diseases, and forward that information to the appropriate
registry.
Modification of Breed Standards
All breed standards are, in effect, artificial. They have been developed
by selectively breeding dogs over the years until they display a certain set
of desired characteristics. Sanctioning bodies have procedures by which they
can change the standards for various reasons.
Physical conformation should be secondary to the health and temperament
of an animal. If genetic diseases are associated with conformance characteristics
in an inseparable way, breed standards could be modified to eliminate the
incentive for breeding to those characteristics once the underlying association
has been identified. In England, through a cooperative effort between the
UKC and veterinary organizations, standards that created a propensity for
disease have been eliminated from all breeds. The Council of Europe has also
enacted resolutions that address the elimination of genetic diseases in dogs.
Registration Organizations
Several organizations throughout the world register purebred dogs. In general,
their charters are similar, and they share the common goal of preserving the
integrity of purebred dog breeds. There are clubs that sanction various forms
of competition, and others that deal solely with medical issues. Some of
the oldest, largest, and most familiar include:
The American Kennel Club (AKC) -- Founded in 1884, it is the oldest and
most prestigious dog registration organization. The AKC includes in its mission:
maintaining and preserving the integrity of a registry for purebred dogs;
sanctioning of dog events that promote interest in, and sustain the process
of, breeding for type and function of purebred dogs; and taking whatever actions
are necessary to protect and assure the continuation of the sport of purebred
dogs. These activities are undertaken with the objective of advancing the
study, breeding, exhibiting, running, and maintenance of purebred dogs
The United Kennel Club (UKC) -- The UKC was formed in 1898, and today provides
an alternative to the more widely known AKC in the United States. It performs
many of the same functions: registry, shows, and stud books. The UKC recognizes
212 breeds, including some that the AKC does not. The UKC offers breed, obedience,
agility, and hunting trials.
Health Related Organizations
These are some of the organizations working on canine medical issues:
Institute for Genetic Disease Control in Animals (GDC) -- In an open registry
such as the one maintained by GDC, owners, breeders, scientists, and veterinarians
can trace the genetic history of any particular dog. In order to control the
increasing presence of genetic diseases, we must know how prevalent such diseases
are in the breed and in any particular dog's bloodlines. The information about
each dog automatically becomes linked in the open registry with their relatives.
An open registry offers this information for the selection of mates whose
bloodlines indicate a reduced risk of producing genetic disease.
The Orthopaedic Foundation for Animals (OFA) -- This organization specializes
in examining and rating dogs with specific regard to hip dysplasia.
The Canine Eye Registration Foundation (CERF) -- An organization dealing
with canine diseases of the eyes.
Other organizations have embarked upon research and education programs related
to health and genetic diseases in specific breeds. Of all AKC registered breed
clubs, nearly three quarters have committees to address health concerns in
their breeds. Nearly half have a code of ethics that includes health issues.
Many breed clubs have either formed or are investigating the formation of
tax exempt foundations to pursue health issues within their breeds.
Among the organizations implementing such health related programs are:
The Scottish Terrier Club of America (S.T.C.A.) Health Trust Fund, which
was founded in 1994 to detect and investigate health problems; monitor health
in Scottish Terriers; participate in research to enhance the prevention of
illness; develop and advocate sound breeding practices; foster safe and healthy
environments; study and share information that promotes better health in all
purebred dogs; and promote and encourage constructive attitudes toward health
concerns. In addition, membership in the S.T.C.A. requires that a Code of
Ethics be signed which supports the issue of genetic disease elimination in
the breed.
The Cairn Terrier Club of America (CTCA). Their Committee for Health Related
Concerns surveyed club members in 1987 for the purpose of determining the
presence and frequency of genetic diseases in the breed. They have subsequently
carried out an intensive education program, engaged the Institute for Genetic
Disease Control to provide their open registry, and produced an award winning
reference manual on Cairn Terrier genetic diseases.
The West Highland Anomaly Task Council, Inc. (WatcH), which was Formed in
the late 1980s for the purpose of understanding and controlling genetic diseases
in West Highland White Terriers. WatcH has undertaken programs for education,
information sharing, genetic counseling, and research. They have conducted
health surveys among the WHWT population, and created a registry to track
several genetic anomalies in Westies.
The Jack Russell Terrier Club of America (JRTCA). Unlike other registries
which register entire litters at birth, each JRT application for registration
is judged on the individual terrier's own merits. Having registered parents
does not automatically guarantee that a terrier can be registered. A terrier
is not eligible for registration until it reaches one year of age and has
attained its adult height, dentition, and other aspects considered necessary
for full maturity. Each terrier's application for registration must be accompanied
several documents, including a veterinary certificate, a four generation pedigree,
a stud service certificate, and color photographs which support the conformation
of the dogs to the club standard.
Many projects are underway around the world in the fight against genetic
diseases in dogs. The approach taken by organizations varies -- some are doing
scientific research while others are providing education. Here is a sampling
of some of these groups:
The Dog Genome Project -- The dog genome project is attempting to map the
entire genetic makeup of the domestic dog (there is a similar project underway
for humans). The result will be a useful tool for the entire scientific community
for the purpose of isolating the genes causing inherited diseases. It is a
collaborative study involving scientists at the University of California,
the University of Oregon, and the Fred Hutchinson Cancer Research Center.
The dog genome project makes all research results available to the scientific
community electronically on the World-Wide Web prior to traditional publication.
Project TEACH of the Pet Health Initiative -- Project TEACH (Training and
Education in Animal Care and Health) was formed to educate about proper animal
care and methods of genetic screening. Project TEACH is an accreditation program
for individuals. All TEACH-accredited breeders, pet shops, rescue organizations
and humane societies will screen animals for potential problems before they
are sold.
AKC Canine Health Foundation -- Established by the AKC in 1995 with a million
dollar endowment. The Foundation is intended to raise money to support health
research which will benefit dogs, and will identify areas for research and
seek qualified individuals to do the research through its Scientific Advisory
committee, concerned fanciers, the Delegate Committee on Health Research and
Health Education, and others. Since the early 1980's, AKC has been a major
funder of genetic research to benefit dogs. The AKC was the principal funder
of the work of Dr. Donald Patterson at the University of Pennsylvania to
develop the Canine Genetic Disease Information System, a database for veterinarians.
Better Companion Breeders Association (BCBA) - Formerly the Better Dog Breeders
Association (B.D.B.A.). A public service agency devoted to the protection
of the buying public. They provide their service free to the public, while
providing members with special services to assist them in operating their
business.
Conclusion
A concerted effort is required by everyone involved with purebred dogs if
genetic diseases are to be eliminated. Science is making progress, but the
time and expense required for the research point toward this being a long
term solution. In the short term, the situation must be addressed using the
tools at hand. Open registries for purebred dogs, administered by their respective
breed clubs or independent registry organizations, appear to be the easiest
and fastest way to a short term solution. They could also provide valuable
corroborative information to genetic disease researchers. Cooperation between
dog breeders, researchers, prospective purchasers, and purebred dog organizations
at all levels is essential if genetically healthy dogs are to become a reality.
One thing is certain -- without the continued attention of many people,
the situation can only get worse.
Selected References
· Clark, Ross D. and Joan R. Stainer, eds., "Medical and Genetic
Aspects of Purebred Dogs", Veterinary Medicine Publishing Co., Edwardsville,
KA., 1983. ISBN 0-935078-24-X.
· Heshammer, A., and Olsson, S-E., et al, "Study of heritability
in 401 litters of German Shepherd Dogs"; J. AM Vet Med Assoc 174: 1012-1016,
1979.
· Hutt, F.B., "Genetic selection to reduce the incidence of
hip dysplasia in dogs"; J Am Vet Med Assoc; 151: 1041-1048, 1967.
· Lemonick MD, "A terrible beauty: An obsessive focus on show-ring
looks is crippling, sometimes fatally, America's purebred dogs", Time Mag.
Dec 12, 1994 :65-70
· Meyers, K., Wardrop, K.J., and Meinkoth, J., " Canine vWD:
Pathobiology, diagnosis, and short-term treatment", Compendium on Continuing
Education for the Practicing Veterinarian, 1992, Vol 14(1), pp.13-23.
· Nicholas, F.W., "Veterinary Genetics", Oxford University
Press, New York, NY, 1987.
· Shook, L., "The Puppy Report: How to Select a Healthy, Happy
Dog", Ballantine Books, New York, 1992, ISBN: 1-55821-140-3.
· Stokol, T. & Parry, B.W., "Canine von Willebrand Disease:
a review", Aust. Vet. Practit. 23 (2), June, 1993. pp. 94 - 103. Willis, Malcolm
B. "Practical Genetics for Dog Breeders", Howell Book House, NYC, 1992 and
H. F. & G. Witherby Ltd., UK, 1992.
· Willis, Malcolm B. "The Genetics of the Dog" Howell Book
House, NYC, 1989 and H. F. & G. Witherby Ltd., UK, 1989.
Copyright 1995 Gary F. Mason. All rights reserved. However, you are encouraged
to copy and distribute this article for non-commercial use with the following
restrictions: You may not modify the article in any way. You must include
the entire article including the copyright notice. You may not charge any
fee for use, copying, nor distribution of the product with the following
exceptions: Non-profit organizations may charge a nominal fee (not to exceed
$5.00) until and unless notified by the author this is not the case.
Eliminating Genetic Diseases in Dogs: A Buyer's Perspective
Copyright 1995 Gary F. Mason. All rights reserved.
Gary F. Mason Reproduced with permission.
