Eliminating Genetic Diseases in Dogs:
A Buyer's Perspective
Author
by Gary F. Mason, gmason@ileaf.com.
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
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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
Registration Organizations
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
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
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
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
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
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,
· 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",
· Shook, L., "The Puppy Report:
How to Select a Healthy, Happy Dog", Ballantine
Books,
· 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.,
· Willis, Malcolm B. "The
Genetics of the Dog" Howell Book House, NYC, 1989 and H. F. & G. Witherby Ltd.,
Copyright 1995 Gary F. Mason. All rights reserved.
Gary F. Mason, gmason@ileaf.com.
Reproduced with permission.
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