Hereditary Defects Advice - Glaucoma in Border Collies

The inheritance pattern for angle closure glaucoma is unknown. As such it it difficult to give the correct advice. A clear from an affected must have abnormal DNA, but how much and whether it will express is just not known.

This form of glaucoma is easily the worst inherited eye disease a dog could get -- both painful and blinding -- so I guess the safest advice is that you avoid breeding from the parents, siblings and offspring of an affected, even though the animals in question have normal angles.

Not popular I know, but nobody I know would want to be responsible for producing an affected dog by breeding from stock linked to known affecteds. Those who do take the risk would be guilty of spreading the disease within the breed.

Prof Peter Bedford

GLAUCOMA - Please read the following links on this subject. Responsible Border Collie Breeders

are testing for Glaucoma now! This is not a witch hunt but it affects us all who have the breeds interest at heart.

Data base are being set up including one on the Borderbility web site. There is also a link below to a u-tube video of vet

explaining about Glaucoma - please watch it.

http://www.caninegeneticdiseases.net/GLX/rsrchGLX.htm
(check on this one the small print at the bottom of the table stating other
breeds sampled - 10 Border collies had been sampled (and this was in 2006)

this one below is a bit technical but worth trying to read.
http://www.vetmed.wisc.edu/Data/CourseMaterial/Miller/Glaucoma.pdf

here is a vet school webpage
http://www.cvm.ncsu.edu/vth/clinical_services/ophthal/glaucoma.html

www.youtube.com/watch?v=zSBZcxEn5KA

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Epilepsy in Border Collies: Epilepsy Studies at the AHT - info for BC owners

Epilepsy Generic Sample submission form

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Pastoral Breeds Health Foundation & TNS Update

Firstly his laymans statement on TNS, secondly answers to several important questions.

I suggest that you apply it all to the news letter.

Can you also add in the details for TNS and any other PBHF donations to Marion Withers at

Rose Cottage, The Green, Bures St Mary, Suffolk, CO8 5JU .

Write on the back of the cheque TNS, this will ensure Marion records it purely for TNS not the general fund. Unless of course people want ot give to the general fund.

We have already sent £2500 to Alan and on the basis of a three monthly report detailing what they have achieved and what they hope to achieve in the next three months we will send another £2500. We have initially agreed to fund up to £10,000 but on a results basis then review, however we need to put funds into the account as we all know research may take longer than initially expected.

If Alan achieves his target before we have spent the £10,000 then we will have more for other research.

The remainder of the existing PBHF funds are to be used for the other potential research initiatives for Epilpsy and Cancer

TNS

Trapped Neutrophil Syndrome (TNS) is an immune problem in Border Collies. Symptoms can be variable which has made it difficult to recognise as a genetic problem. A common symptom is recurrent infections in young pups, but some develop abnormal faces a few weeks after birth while others appear normal until vaccination when they have a bad reaction and never recover, while others live to several years of age with only occasional problems. Many cases of 'fading puppy syndrome' have turned out to be unrecognised cases of TNS. TNS is a genetic disease with recessive inheritance (like CL) which means that to have an affected puppy, both parents must be carriers (ie one defective and one normal copy of the gene but showing no adverse effects) and about one quarter of such litters will be affected.

Dr Alan Wilton and Jeremy Shearman at the University of New South Wales in Sydney have identified the gene that is defective in TNS through study of Australian affected litters. They can trace the path of this TNS mutated gene through the pedigrees and predict TNS carriers. They have not had access to the English TNS cases reported recently but are keen to see if it is the same problem and if they can detect the defect in English lines with current technology. TNS has also been reported in Working Border Collies in Australia so the mutated TNS gene may have been around in the breed for a very long time and all TNS cases have a common cause and origin.

The current TNS research is to identify the actual DNA change that causes the defect in the TNS gene. This would allow testing of any dog for carrier status of TNS without any information about its pedigree. Information from DNA testing can then be used by breeders to gradually eliminate this disease from the breed.

Alan Wilton

School of Biotechnology and Biomolecular Sciences

University of New south Wales

NSW 2052

1) How accurate is your current test percentage wise ?

The current test is more than 99% accurate for identifying carriers in samples closely related to known carriers from the Australian lines with TNS. We are just following the DNA with the mutation through the pedigree. If there are large gaps in the genotyping of animals in the pedigree between the known carriers and the tested animals it becomes more difficult to do that and leaves room for possibility of misinterpretation. Though everything is checked human error is always a possible source of error.

If, in the unlikely event, there are other sources of TNS mutations the current test may not recognise them. For example, I cannot tell whether the current test is applicable to the cases of TNS in the purely English lines until I get enough samples of animals related to those cases and do further research.

2) How much more accurate will the DNA test you are trying to define percenatge wise?

The DNA test we are developing will be 100% accurate as it will look directly at the cause of the problem. It will be applicable to any Border collie regardless of its pedigree and needs not be closely related to known carriers. Whether the cause of TNS in the pure English lines is the same as in the Australian lines is yet to be determined and it will be part of the continuing research to develop a test for all types of TNS.

3) Will those dogs that have been already tested under the existing test have to be re tested to guarantee if they are clear, a carrier or affected?

When the new test is available, as part of our quality control program we will retest a large sample of carriers and clears as defined by the current test to ensure there are no discrepancies. If, in the remote chance there are, the information will be widely publicised, and the samples in hand tested as part of the research to provide as much information to the breeders as possible as to possible lines affected.

4) Is the mutation , single recessive or multiple recessive?

The mutation in the Australian lines is a simple single recessive allele with all cases arising from a common ancestor. Only when we develop the test will we be able to determine whether TNS in the English lines is caused by the same mutation in the same gene, a different mutation in the same gene, or a mutation in a different gene.

There is now quite a lot of concern with in the breed and could potentially stop people using dogs and bitches for breeding which are not actually going to create a risk to the breed.

Since we have a reliable test for TNS from the Australian lines now, my advice as a geneticist is that known carriers can still be bred from if they are mated to TNS clear animals. The pups can then be tested at a few weeks to determine which are clear and can be used for breeding future generations, and which should be used only as pets. This breeding strategy allows elimination of the disease from the breed without reducing the available breeding population as a reduction could lead to new genetic problems arising.

Alan Wilton

I hope this helps explain the current situation.
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Hi everyone,

Please see below a response from Alan Wilton regarding validation of existing results after he defines a full DNA test.

Can you ensure that you members and especially your PBHF representative are aware of this. Please use this information for your web sites and newsletters.

Alan,

I have been asked about your comment regarding -- Once the DNA test is defined that some of the original test will be repeated to cross check results. Members have asked if there would be an additional charge for those dogs re- checking, I have said that I believe that this work would be part of you validating your research only and would not require additional payments. Can you just confirm in your own words, I appreciate this sort of question is a pain but as stated before our experiences over the CEA research have left many people wary.

Richard,

Regarding confirmation of current TNS test results with the test for the mutation when it is available.

A large number of samples will be done as part of the research to ensure there is a 100% correspondence for the two results. Samples from all lineages predicted to be carriers will be tested and as many as practical non-carrier lineages. No charge will be made for this quallity control testing. The owners will be notified if there are any unexpected discrepancies the information will be circulated through breed clubs and websites. If any unexpected discrepancies then all of the results will be reanalysed and the owners informed of any changes in TNS status predicted from the tests at no charge.

Alan Wilton

School of Biotechnology and Biomolecular Sciences

University of New south Wales

NSW 2052

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I would like to thank the Pastoral Breeds Health Board very much for supporting the TNS research and providing the funding that supports my part of the work with a scholarship. It will allow me to concentrate more on the research and less on the business of finding food and shelter. A little bit about myself: I am a 23 year old PhD student at the University of New South Wales in Sydney, originally from the north coast of New South Wales in Australia. I did a B.Sc and in 2005 started working on TNS for my Honours research year. During that time I have gathered the samples to facilitate the research and identify the gene involved in TNS. When I finish my PhD I think I will continue in the field of genetic diseases and possibly move onto human genetic disease. However, working on the dog genome has given me an interest in the genetics of behavioural and physical characteristics. Dogs are the single greatest example of selective breeding for physical characteristics and behaviours giving huge potential for research into the genes responsible for characteristics such as aggression, body size, curiosity and intelligence to name just a few, which would be interesting areas to research. Having never travelled outside of Australia before, travel is pretty high on my list of things to do when I finish my PhD, or hopefully earlier if I get an opportunity to travel to an international conference, where scientists meet and share ideas. I consider myself lucky to have found Trapped Neutrophil Syndrome as a project for my PhD and hope to have it solved by the end of this year. It would not be possible without the support of all the Border collie clubs and their members. The willingness of breeders to come forward and confront this disease has revealed a problem more extensive than anyone imagined. With continued support and openness by breeders about this disease we will be able to test for carriers so that breeders can avoid matings which could produce affected pups and through a slow process of selective breeding remove the disease from the population entirely.

Jeremy Shearman

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