CT Test Results Summary



Liver Biopsy.


Copper toxicosis was first recognised as a specific hepatic disorder by histo-pathological examination of liver tissue samples obtained by biopsy.  Subsequent research established that it was a genetic disorder, the presumption being made that it was the result of an autosomal recessive mutation inherited according to classical Mendelian principles.


Until such time as a genetic test could be developed, diagnosis continued to be based on laboratory examination of liver biopsy samples.


This was viewed with some misgivings and there was a general reluctance on the part of many breeders to use this testing procedure.  None-the-less, thanks to the sterling work of Fiona Craig and the members of the Liver Malfunction Committee many breeders were “persuaded” to have their dogs tested.


Unfortunately, the Bedlington Terrier Health Group does not hold details of the test results of these dogs’



The CO4107 DNA Marker Test


The first DNA test to be introduced for diagnosis of the copper toxicosis status was the CO4107 Marker Test.  This was an indirect test in that it tested for the presence of specific markers that were considered to be closely “associated” with the CT gene but not the actual gene itself.  This test was developed by Vetgen in the USA and was was first used by the Animal Health Trust on the 9th July 1996, after a trial to assess its suitability for use in the UK.

A total of 885 dogs were tested at the AHT using the marker test before it was replaced by the COMMD1 test.  Of the 885 dogs  that were tested, 829 had been registered and the remaining 56 were unregistered dogs.


Details of the results of these tests were passed to the Health Group by Stuart Yearley, who was the Secretary of the now disbanded Liver Malfunction Committee.  The Health Group now holds a copy of these results on a database.


During the period July 1996.-.June 2005, the period which equates approximately to the period over which the marker test was used, there were 3710 Bedlington terrier puppies registered by the Kennel Club.

 

From this information an estimate of the approximate percentage of registered puppies tested can be calculated:


(829/3510) x 100 = 23.62 %



A Breakdown Summary of the AHT CT Marker Test Results.








 Summary -  All the AHT Marker Test Results








1.1 "Normal"

1.2 "Carrier"

2.2 "Affected"

Total






Non-Registered Dogs

17

26

13

56

% Non-Registered

30.36 %

46.43 %

23.21 %

100 %






Registered Dogs

452

308

69

829

% Registered

54.53 %

37.15 %

8.32 %

100 %






Total Nos of Dogs

469

334

82

885

Percentage

52.99 %

37.74 %

9.27 %

100 %








Publication of COMMD1 Results by the Kennel Club.


For some time the Health Group have been trying to establish a way in which results of COMMD1 tests for copper toxicosis could be made available to interested “parties” without falling foul of the confidentiality requirements of the Data Protection Act.


The Health Group are fully aware of the fact that anomalous results had occurred with both the DNA C04107 marker test and the DNA COMMD1 test for copper toxicosis.  Analysis of available data and comparison with liver biopsy results indicated that neither DNA test was 100% accurate, the conclusion being that a second gene was involved.


However, despite this, the Health Group agreed, after considerable discussion, to ask the three breed clubs for their approval to join the KC Scheme for Publication of COMMD1 results on their behalf rather than delaying any request to join the scheme until the question of “a second gene” had been resolved and a new DNA test developed.  At the 2011 round of AGMs the members of the clubs agreed to the Health Groups request and this scheme is now in place.


The Kennel Club, in their December, 2011 edition of the Kennel Gazette, published the following statement.


“A DNA test for copper toxicosis (COMMD1) in Bedlington Terriers has been approved by the Kennel Club.

Offered by the Animal Health Trust (AHT), test certificates will be sent directly to Clarges Street where the result will be added to the dog’s details on the registration database. This will trigger the publication of the test result in the next available Breed Records Supplement and the result will also appear on any new registration certificate issued for the dog and on the registration certificates of any future progeny of the dog.


Owners of dogs who have already had their dog(s) DNA tested for this condition can send copies of the DNA certificates into the Kennel Club and the data will be added to the dogs registration details.  If the owner includes the original registration certificate for the dog (not a copy) a new registration certificate will be issued, with the DNA result on it, free of charge.”


For further information on this scheme please contact Miss Aimee Llewellyn at:


aimee.llewellyn@thekennelclub.org.uk






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Copper Toxicosis


The DNA COMMD1 Test.


The Animal Health Trust introduced the COMMD1 test  on the 12th July 2005 and since then has carried out 924 tests up to the 25th August 2017.  A summary of the results is shown in the following table - of these results, 605 relate to registered dogs.


The Breed Record Supplements (BRSs AF3 - AU2), covering the period approximating to that during which the COMMD1 test has been available, show that 5815 Bedlingtons were registered.

 

Again, using this information, it is possible to calculate an approximate percentage of registered dogs that have been tested using the COMMD1 test (as at 25.08.2017)


(605/5815) x 100 = 10.4%



A Breakdown Summary of the AHT CT COMMD1 Test Results