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THE HOW AND WHY OF THE GDC KinReport
 
 

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The GDC KinReport is a new tool to provide the breeder or prospective owner with 
the genetic profile of a chosen dog. The report shows all the dog's relatives 
which are in the registry and whether or not the dogs were evaluated as affected 
or not affected. The report shows which diseases should be checked for each 
breed and which have been evaluated in the chosen dog and its relatives. 
Whether a dog is clear or a carrier can best be determined by reviewing the 
progeny. Some insight is obtained by reviewing the siblings and half siblings, 
but very little useful information can be acquired from the standard AKC or 
breeder pedigree.
The preferred breeding animal is the one that has the fewest affected cases 
amongst the progeny. The affected dogs are known with certainty to have the 
affected genes while the 'normal' or unaffected cases can be either free of the 
unwanted genes or pass on the unwanted genes to their offspring.
HOW TO READ THE GDC KinReport 
The report consists of three main tables and a pedigree. The pedigree is 
presented to show which dogs are in the registry and whether or not they have 
been evaluated by GDC. The tables will show all the siblings, half siblings, and 
offspring of a dog, and the same for both parents. The important data are the 
genetic disease evaluations for each of the dogs.
The tables are assembled by a computer program which links all the dogs together 
on the basis of the parents. It doesn't matter if the original entries come from 
different owners or breeders, they will all be found and added to the record.
The Pedigree
The pedigree is not intended to replace the formal AKC pedigree. It is basically 
a road map. For this reason the GDC dog number precedes the dogs name, which 
does not include titles. Other information such as, birth dates, co-owners etc. 
is not included on the line. The GDC dog number is used to tie all the data 
together. For example, the Sire's number is given on the other tables and his 
name can be found by referring to the same number on the pedigree. See page 2 of 
Appendix A (The actual KinReport).
 
The asterisk, '**', shows that the dog has been evaluated and is in the 
registry. (It can be thought of as being a gold star.) If the dog is without an 
asterisk, it had been entered as an unevaluated parent. 
 
The pedigree goes back only to great-grandparents, 3 generations, because the 
common genes of an ancestor are rapidly attenuated by each generation. Only 1/8 
of a dog's genes are derived from a great-grandparent, because the number of 
genes contributed by each ancestral level is reduced by 1/2, as half come from 
the mother and half from the father.
However, the pedigree can be used to go deeper into the ancestors data by asking 
for another KinRport on a grandparent or great-grandparent. Sometimes it is 
helpful to look at a KinReport on siblings or progeny. If there is reason to 
think that the pedigree would link with other dogs in the GDC registry, dogs can 
be entered from a complete pedigree.
You may notice that all of the dogs in Appendix A have peculiar names with 
kennel names that don't match the breed. This example has been scrambled to 
avoid any possibility that the dog can be identified. We asked the computer to 
make a new three part name by random selection from the entire data base. If you 
recognize a breeder, that is good, as that breeder is taking advantage of the 
latest tools to control the genetic disease in his or her kennel. We are proud 
to be working with leaders in the field.
The Report Tables
The third page, Table II, gives the sibling, half siblings and off spring of the 
dog being considered. This table is placed first as it has the greatest 
significance in predicting genetic qualities. Please see the sample KinReport in 
Appendix A and the Glossary in Appendix B for an explanation of the codes on the 
entries. 
The dog's names, siblings, and progeny are listed in rows down the page and the 
diseases in columns across the top, Appendix A, page 3. The first group of dogs 
listed under 1: are the siblings and half siblings, and the second, 2:, are the 
offspring. The selected dog will always appear in the list of siblings. The 
siblings and progeny are ordered by birth date, to facilitate the identification 
of litters. GDC asks for the number of each dog's litter mates. When this has 
been provided, the number appears in the last column 'Ltr Size'. 
Tables III and IV on pages 4 and 5 have the same information as Table II but 
they relate to the Sire and Dam who is listed near the top of the page. The 
parents progeny will also appear in the sibling group of the dog being reviewed.   
The Genetic Disease Columns 
The genetic diseases which are listed and identified with the symbol ^ are those 
that have been selected as being important to that breed. These are chosen 
either by GDC's advisory panels in view of published literature or have been 
added at the request of a breed club. The recommended tests are breed specific 
and will be different for a KinReport issued for different breeds. As many as 10 
genetic diseases can be listed on each KinReport. 
The recommended list of genetic diseases for the breed will always show on the 
report. If an additional disease has been evaluated for a particular dog, that 
column will appear on that table, but not on the other tables. That disease 
column will be identified with the symbol -. None of the data in a research data 
base will appear on the KinReport. For example, if a dog has been evaluated for 
hips and epilepsy, only the hip results will be on the report. 
Conclusions 
The report has been designed to bring the essential information on to one form. 
It does not include the details of an affected elbow or eyes which appears on 
the GDC Evaluation report given to the owner at the time of registration. For 
example, the elbow may show FCP or arthrosis. If more detailed information is 
desired, please ask your veterinarian to contact GDC.  
You may want to talk to your veterinarian about the conclusion found from the 
KinReport. Your veterinarian should call GDC with any questions. 
A genetic report is not valid if the actual genealogy is different from the 
submitted pedigree. At some future time the fancy will want to use micro chips 
or DNA parentage testing, but until that time GDC has to depend upon the 
accuracy of the submitted data and its verification by the veterinarian.  
We appreciate the opportunity to work with you in helping to control genetic 
disease in your dogs. If you have further questions or comments, please contact 
us at GDC, phone or fax 530-756-6773.  
THE WHY OF THE GDC KinReport
The Genetic Basis of the GDC KinReport 
The usefulness of the KinReport is based on the simplest of the classical 
genetic principals. A dog may pass on the genes for a characteristic even though 
that characteristic can not be seen in that individual. This is illustrated by 
the example in Appendix C.
 
Exactly the same rules prevail for many of the canine diseases which arise from 
a single gene, e.g. Progressive Retinal Atrophy (PRA) or Sebaceous Adenitis 
(SA). Even if the disease is carried by several genes, polygenic, the principles 
are the same. Hip and elbow dysplasia are examples of proven polygenic diseases.   
Mass Selection as Promoted by OFA 
It is disappointing, but the widely practiced mass selection procedure has not 
produced significant reduction in the frequency of hip dysplasia over the past 
30 years. Mass selection calls for breeding only normal to normal phenotypes, 
that is parents that do not show the disease. The problem is that a normal dog 
still carries hip dysplasia genes. This is why a severe case of hip dysplasia 
often occurs even though the breeder has been conscientious and bred only 
unaffected hips through several generations.
For all practical purposes all the dogs in all breeds, except perhaps sight 
hounds, should generally be considered to be carriers of the polygenic disease, 
hip dysplasia. As far as is known, no dog has ever been shown to be entirely 
clear of the hip dysplasia genes. The finding of such dogs would be a great 
blessing to any breed. 
The advice of the OFA and veterinarians to breed only those dogs that do not 
show the disease is right, but is not enough. It is incorrect to breed dogs that 
are clearly affected, severe or moderate, because it is certain that the dog 
carries the deleterious genes. However, the absence of the disease in a parent 
tells us little about the genes of that dog; we can not tell from the phenotype 
alone, if the dog is genetically clear or is a carrier. That is we can not 
predict how many of the offspring will have hip dysplasia.
The Records on Affected Dogs are Very Important
Our focus needs to be on those dogs that are affected, with either a single gene 
or a multi-gene disease. These dogs are the ones that we are certain have the 
unwanted genes which can be passed on to its offspring. A major weakness in the 
OFA procedure of mass selection is that the information on the affected dogs is 
not released and is not linked through the parents to the relatives. Even if 
OFA, a closed registry, were to release the data, it would be incomplete because 
many breeders do not send in the radiographs which they believe shows their dog 
to be affected. The closed eye registry of CERF suffers from the same 
deficiency, but we don't know how seriously.
Another weakness of the current OFA and CERF closed registries is that firm data 
is not available on the incidence or prevalence of a disease within a breed. 
This information is required in assessing the progress in controlling the 
disease. If the disease is polygenic, the average frequency of the disease 
within the breed is important in selecting breeding stock. The careful breeder 
will try to breed only those dogs that are 'better than average'.
Although the rule of thumb to 'breed better than average' has been used since 
the beginning, it needs to be redefined when breeding for control of genetic 
diseases. The rule is most useful if the heritability of a trait is high and the 
trait is a simple observable, that is the relation between phenotype and 
genotype is high. Almost all breeding for confirmation follows this rule.
In breeding for control of genetic diseases, we can not see the genes that 
govern the trait or disease, except in a few cases like GCL in Cairn terriers or 
PRA in Irish setters. In time we will see more tests using markers or the gene 
itself, but to develop a test will be very difficult for polygenic diseases like 
hip dysplasia. The best that we can do now is to observe what the dog produces 
in the offspring. 
Back to breeding better than average. Better means that the progeny or siblings 
have fewer relatives that are affected and average does not refer to the average 
of the general population, but rather the average of the sub -population of the 
breeders line or kennel. If a breeder ignores the rule of nature and adds 
breeding stock that is genetically inferior to her line's average the inevitable 
regression to the mean will occur.
The GDC KinReport will list whether or not a dog is affected or unaffected for 
many of the genetic diseases and with a grading for some. 
It is well known that no diagnostic procedure is without the possibility of 
error. The practice in medical science has been to categorize a result as being 
'negative' or 'positive', to simplify the use of the data. This corresponds with 
our use of 'affected' or 'unaffected'. A false positive is reported if the 
animal is actually free of the disease but the test shows it to be affected. A 
false negative occurs if the dog is affected but the test shows it to be disease 
free, that is unaffected.  
It is unfortunate that the OFA has placed great significance on whether or not a 
dog is classified as 'normal'. If the dog is certified as normal a number is 
issued, and the assumption by many breeders and prospective owners is that the 
dog is passed for breeding, and if it is graded dysplastic the dog should not be 
bred. One problem with this dichotomized grading is that the dog may be bred or 
not bred on the basis of a result which may be a false negative or a false 
positive. GDC follows the practice of reporting certified dogs to respond to 
client requests.
The OFA has traditionally recognized this problem of inaccurate diagnosis by 
using three readers, knowing that not all readers will read the x-ray the same. 
This is not to fault the readers as we expect and know that readings can be 
different by one or even two grades, depending on the evaluators. A little 
reflection shows that the use of three readers does provide some degree of 
quality control but does little to improve the accuracy on a single dog. If the 
finding is close to a boundary, then there may be a 25 to 50% chance that the 
finding will be wrong. In fact the consistency provided by one reader may at 
times be preferable to the variation introduced by the selection of multiple 
readers. Some groups favor the use of a single reader, as is done in Sweden. GDC 
is reviewing the feasibility of providing the client with a choice of one reader 
rather than the traditional 3. 
Although false positive or false negatives are of some concern in the genetics 
of hip dysplasia, the problem for many breeders is the affect on the sales of 
the pups. In many breeds the value of the pups is dependent on having certified 
parents and even grandparents. However, experience and analysis shows that a dog 
should not be ruled in or out of breeding solely on the basis of the phenotype 
of the hips, because multiple factors should influence that decision. 
However, in the case of a single gene disease, PRA, a false negative is of great 
concern. The reason is that one affected progeny shows that the parent is a 
carrier and hence, a single false negative may encourage the breeding of a dog 
that is a carrier with the resulting wide spread dissemination of PRA genes.   
Probabilities
  The breeding of dogs remains an art which can be enhanced by the assiduous use 
of the statistical information which is available from the GDC open registry. 
The more information in the registry about siblings and offspring the better 
will be the results. If there are enough cases an analytical approach can be 
helpful, but can not replace a breeder's knowledge of the whole dog.
 
mep 5/27/95
7/25/99  
Appendix B
GLOSSARY OF TERMS
      _ This symbol appears in the disease columns if the test is not known to 
      be important for that breed, but one or more dogs have been tested.
      This symbol may appear for a breed even if it is known that the disease is 
      genetic in another breed. For example, the mode of inheritance of SA is 
      known for Standard Poodles, but has not been shown to be hereditary in 
      Bernese Mountain Dogs. If it is shown to be genetic in BMDs and is deemed 
      to be important the classification will be changed to ^, and the column 
      will appear on each BMD KinReport. 
      ^ This symbol appears in the disease columns, if the test is recommended 
      for that breed, either by the breed club or is documented as being genetic 
      and is generally considered to be important. Recommended test will be 
      added to each breed as more information is available. Not all possible 
      tests will be added to allow focus on the important diseases.  
      ? If the question mark appears in the Litter Size column it indicates that 
      the owner has not supplied the number of puppies.  
      A, B, or C The code which tells that the evaluation could not be completed 
      and a repeat is recommended. If the test was repeated the diagnoses will 
      replace the letter code.
      Bil Bilateral Dysplasia:
      Used primarily in orthopedic evaluations to indicate that the 
      manifestations of the disease show on both joints. 
      Uni Unilateral Dysplasia
      This usually indicates a milder classification. The joint will be 
      classified as affected, and no certification number will be issued.
      CMO Craneomandibular osteopathy.
      A disease that affects some terrier breeds.
      Dam Number The unique number assigned by the GDC computer for the dam of 
      the dog. This number provides the computer linkage to progeny and to 
      pedigree.
      Dog Number The unique number assigned by the GDC computer to the dog. This 
      number provides the computer linkage to progeny and to pedigree.
      DrwfChondrodysplasia:
      Currently a research data base for dwarfism  
      Elbows
      Elbow joints:
      The general category for orthopedic diseases of the elbow joints. The 
      details of the disease have been presented on the GDC evaluation form 
      which went to the owner and veterinarian.  
      Aff
      Affected:The evaluation of the site shows that the dog is affected with the 
      disease, and is certain have the deleterious genes. No further testing is 
      required, even if the dog's age is less than the usual certification age. 
      In some diseases, like SA, the result may be sensitive to the site of the 
      biopsy. In this case, the diagnoses will be based on the sample that shows 
      the disease, and will not be changed with subsequent testing. In the case 
      of hip dysplasia, the dog will be classified as dysplastic, even if only 
      one hip shows malformation or arthrosis. The dog will not be issued a GDC 
      certification number.  
      Eplp
      Idiopathic Epilepsy:Currently an all breed research data base. The affected dogs are 
      identified by a questionnair.
 
      Eyes
      Eye diseases: The general category for eye diseases. The specific diseases, progressive 
      retinal atrophy (PRA), cataracts (Ctrct), retinal dysplasia (RD), corneal 
      dystrophy (CDyst), and entropian eyelids (Entrp) will be listed.   
      Hips 
      Hip joints: The general category for orthopedic diseases of the hip joints. The 
      details of the disease and the grading have been presented on the GDC 
      evaluation form which went to the owner.   
      Hist 
      Histiocytosis: A tumor type which is known to be genetic in the BMD. Tumor types which 
      are in the research data base will not appear in the tumor column.
         L-P 
      Legg-Perthes disease: An orthopedic disease of the hips   
      SA 
      Sebaceous Adenitis:A skin disease affecting the sebaceous glands.  
      Shld 
      Shoulder joints: The general category for orthopedic diseases of the shoulder joints. The 
      details of the disease have been presented on the GDC evaluation form 
      which went to the owner.   
      Sire Number: The unique number assigned by the GDC computer for the 
      sire of a dog. This number provides the computer linkage to progeny and to 
      pedigree.   
      Mast 
      Mastocytoma (mast cell tumors): A tumor type which is known to be genetic in the BMD. Tumor types which 
      are in the research data base will not appear in the tumor column.  
      MPL
      Medial patellar luxation: A disease of the knee.  
      Stfls
      Stifles or knee joints: The general category for orthopedic diseases of the knee joints. The 
      details of the disease have been presented on the GDC evaluation form 
      which went to the owner.   
      Tarsus
      Tarsus or hock joints: The general category for orthopedic diseases of the hocks joints. The 
      details of the disease have been presented on the GDC evaluation form 
      which went to the owner.  
      Tumor
      Tumors or cancer: A registry of tumors that have been diagnosed histologically. There is no 
      unaffected category in the registry as it is not practical at this time to 
      carry out a screening procedure. All of the tumors other than 
      Histiocytosis and Mastocytoma are carried in the research data base and 
      not reported on the KinReport. Seventy different tumor types are in the 
      research data base.  
      Uni
      Unilaterally Dysplastic: Used primarily in orthopedic evaluations to indicate that the 
      manifestations of the disease show on only one joint. This usually 
      indicates a milder classification. The joint will be classified as a 
      affected and no certification number will be issued.  
      Unaff
      Unaffected:Tarsus or hock joints: Appears in a disease column, if the test showed no evidence of the disease 
      at the time the evaluation was preformed. The dog will have been issued an 
      GDC certification.  
      Yng 
      Young: This dog was below the age for certification by GDC, but did not show a 
      signs of the disease. A later examination is recommended.  
      Recheck Date: 
      An Unaffected evaluation for the late onset single gene diseases, like PRA 
      and SA, will carry a date. This date signifies when a recheck is due, 
      usually 1 year. An unaffected grade before the date of recheck date does 
      not signify that the dog is currently free of the unwanted genes. It 
      simply means that a recheck is recommended.

  Appendix C
PRA TRAIT VS. PRA DISEASE 
Dogs with PRA trait only do not have and will not get PRA disease, but they can 
pass it on to their offspring if their mate also has PRA trait or has PRA 
disease. The possibilities for a pup's eyes depending on the parents' traits are 
(1) shown below:
  (Key) 
  AA - Normal retina  
  Aa - PRA trait  
  aa - PRA disease  
* 
1 -Parents: AA + A a      Genetically clear + carrier of trait
    Puppies: AA, Aa,AA Aa      2 genetically clear, 2 unaffected carriers  
 
Case 1 shows the difficulty of identifying the genetically clear from the 
carriers
2 - Parents: AA + aa      Genetically clear + affected
    Puppies: Aa, Aa, Aa, Aa      4 unaffected but all carriers 
Case 2 shows why an affected dog should never be bred unless the puppies are 
neutered or given limited AKC registration. The puppies are healthy but the 
carriers can spread throughout the breed. 
3 - Parents: Aa + Aa       Unaffected carrier + unaffected carrier 
     Puppies: AA, Aa, Aa, aa      1 clear, 2 carriers, 1 affected
Case 3 is most common, the problem is that the clear dog can not be identified 
from its phenotype. This is a case of breeding normal to normal, as in the mass 
selection procedure.
4 - Parents: Aa + aa      Carrier + Affected
     Puppies: Aa, Aa, aa, aa      2 carriers, 2 affected 
Case 4 as no genetically clear dogs as offspring.This case is to avoided.
5 - Parents: aa + aa      Affected + Affected
     Puppies: aa, aa, aa, aa      4 affected
Case 5 is the worst of all possible choices.
6 - Parents: AA + AA      Clear + Clear
     Puppies: AA, AA, AA, AA      4 clear
Case 6 is the best of all possible choices and is the goal for genetic disease 
control.
This was modified from a chart on sickle cell anemia in humans which appeared in 
the March 05, 1995 Los Angles Times. Much of the science of genetics comes from 
human medical research and is then applied to animals. Sickle cell anemia and 
PRA are both autosomal recessive traits that share the same genetic rules. 
Polygenic diseases, e.g. hip dysplasia, do not fit this model exactly, yet there 
is some commonality which helps provide insight to the process.