There is not yet any reliable gene test to show if a dog is a GPRA carrier. We only know that the sire and dam are proven carriers when the offspring is affected, furthermore the siblings could be affected/carriers too.

The KC publishes all the eye failures. I find it totally unbelievable that some of the breeders know nothing about the inheritance mode of the GPRA and happily breed from heavily affected lines!

No offspring from a proven GPRA carrier should be used for breeding. Living with a blind dog is heart-breaking!

Not quite sure what the question is here. I am at the moment involved in a discussion with a German woman about this very subject. There is several companies offering a DNA test for CPRA but as you say, it is not 100% reliable as yet. As to the reasons why this should be, well, one person's theory is probably as good as another's! My pet theory is this:-

If as an example, you mate an English Springer carrier to a Labrador carrier it is unlikely that the puppies would develop PRA. The reason as I understand it is that the CPRA gene appears at a different place in the genome of the two breeds. If you look at the formation of the Labrador breed, so many different breeds were involved (and the same holds true for just about every breed). This would have brought the hereditary problems of those breeds over into the Labrador. Some of course would have been so scattered that over the course of time the affected gene would be bred out. Other affected genes would be rather more prevalent and would become established within the breed.

From this theory it is easy to see how a problem could stem from a number of different genes (Places within the Labrador Genome) even though the actual ailment, GPRA, is identical.  

As an organiser of eye testing sessions I do realise the shortcomings of the visual test which we offer. It is not perfect because it cannot tell you what has not actually developed yet. But neither is the DNA test without it's shortcomings for the reason that I do not believe the scientists have found all the markers yet. There is still no substitute for research into the ancestors of your bitch and any stud dog you are thinking of using. This is still the best way of insuring the resultant puppies have the best chance.

I've talked Labrador because this is the breed I am most familiar with but exactly the same would apply to any breed.

Regards, John

This link may be of interest

There now is a DNA test for CEA released November 2004 & yet to be mentioned in the show dog press !

I was about to mention the Optigen test, I know breeders who have used it and got A1 clear which means they are not carriers and will never get prcd-PRA. 

I am still to be convinced that the Optigen test is as reliable as their stated 99.75% certainty of not developing CPRA in Labradors or 99.5% chance of not being a carrier. (These figures were taken from their own A1 pass certificate)

We have seen cases at our eye testing in the past which have been DNA passed which are actually suffering from CPRA. Admittedly Optigen have updated their Labrador test as at July 2003 so I await developments on that front. I have to say that if their claims can be upheld that that could really be marvellous for the breeds! We would then really be in a position to eliminate this from the breed! PRA is the bad one because it ends in blindness but the numerically big one is hereditary Cataracts and this is the one I would love to see a test for because, as in a lot of cases it is late forming a breeder could test their dogs religiously only to find that after the bitch's breeding life is over the bitch develops cataract. The poor breeder is then left with the knowledge that they have bred a whole load of possibly affected dogs! A terrible legacy!

Regards, John

Optigen at least are doing the research & are not resting on their laurels as they are still asking for b;ppds from sufferers of cpra

They have been the only ones to do CEA research & after a recent scare when it looked like a very successful stud dog(ISDS BC)who after producing around 50 litters of screened normal puppies had produced a puppy with little vision due to CEA & only after DNA proved he was not the father, it is very wlecome(no reason to stop eye testing puppies of course)

I repete what I said Moonmaiden.

<<I have to say that if their claims can be upheld that that could really be marvellous for the breeds! We would then really be in a position to eliminate this from the breed!>>

??? I was only pointing out that they are still asking for bloods from affected dogs to do more research not saying they were foolproof, there is very little research being fonr by anyone else

Retreating back to lurk mode

The exact wording reads "OptiGen Tests PRA-Affected Dogs at NO Cost"

Who would actually want to have their affected dogs tested? They know the results before the test! It would have been better for them to ask for DNA samples from affected dogs to be sent to them to assist them in their research rather than the implied heading that they were somehow doing the people a favour.

I know this kind of research is expensive but at $312 they are going to do very well out of it. Also, by the fact that the big American laboratories have patented almost all interesting genomes including vast tracts of the human genome no one else is able to get a look in. You no longer own the rights to examine your own genes!

Yes, I'll give them a pat on the back if they can really do what they say but they will have to prove it to me first.

Optigen have been requesting blood from affected dogs & or families of known affecteds for at least 5yrs that I know of & although they say they test at no cost what about the cost to owner of affected dogs to have blood drawn by vet & then sent off to them?????? For them to tell you what you already know hmmmm so who benefits there then????

Moonmaiden do some research & see why Optigen are the only ones testing & why Newmarket stopped, or do you think Optigen are all heart? A firm called HealthGene used to do a dna pra test for affected/carriers for Labradors a few yrs ago but it was taken off the market, it`d be interesting to know if there was/is any conection between those 2 companies.

Christine, Spain.

Yes I am soooooooo very stupid that all commerical firms only think of the animals No they don't they only think of the profits & falsify the results time after time so mugs keep on paying them to give them false results & only charities do good research like the AHT, but hang on the AHT are charging CKCS owners £800 + for MRI scans for SHM screening lasting 15 minutes whereas two private vets charge between £150 & £200 +VAT for the same MRI scan so the private vets are making lots of money & not being funded ?because they are profit making

Taking bloods cost little & I know my vets waive all charges if is for health related research(although the BVA say it cannot be done solely for research purposes!only the excess from tests for illnesses can be used)

So we should disregard this company & wait for a nice charity to do the research so that in maybe 25 years time they might if the funding lasts find the mutant or marker genes for a test ? & if there is no funding the research will cease & KC BC with CEA & that produce CEA dogs will still be bred from(& this is happening)

Oh grow up Moonmaiden, what a right little tantrum you`ve just thrown.

Tell me, what would you think if the company doing the dna testing got it wrong? Which would be worse, having a clear dog failing & being branded affected or having an affected dog pronounced clear & unaffected?

*Taking bloods cost little & I know my vets waive all charges if is for health related research*

Well bully for you. Do you think the UK is the centre of the universe????  What about other folk & vets around the world or I suppose UK`s got the monoply on dog health then, or just maybe vets over here haven`t got quite as clued up on it & live in the real world of pretty realistic prices & unfortunately charge just to make a living! Taking blood costs time, as does the packaging & sending it to USA & why should anyone be out of pocket to help a firm make money from a test they are selling as almost 100%. Almost is neither here nor there. But one thing it`s not, at mor than $300 it`s not cheap & thats a fact.

Christine, Spain.

And heres another reply to another of your quotes
*No they don't they only think of the profits & falsify the results time after time so mugs keep on paying them to give them false results*

No I was only ONE of the silly mugs who paid HealthGene to give me a false a certificate. But had the satisfaction of them withdrawing their dna test that was known at the time to be way wrong. And no, actually, it was saddness that they could be marketing that test that people had a whole lot of hopes riding on.

What I`m totally sick of is so called experts/companies/vets anyone else who tries to tell animal owners that this disease that disease can be prevented if you do such a test feed that food give the other medicine use such a vaccine & folk saying right ok I`ll do that then being so upset/bewildered when things don`t go like they should. No, science isn`t exact, no breeding is perfect, never will be. We all need to question the experts, do our own research, delve into things more instead of taking the experts word for it.
I aint holding my breath for the test to become %100............hope not too many folk are either.

Christine, Spain

As a geneticist(no I am not employed by any company I am not involved with any commerical company either) I am well aware that genetics is not an exact science & there will always a margin of error & the unknown for a long time to come, which is why it has to go hand in hand  with what every physical tests are available

Owning a blind dog is not what I would wish on anyone but as far as I am aware dogs do not die from going blind(some owners might have any blind dogs killed)but there are no genetic conditions such as PRA(in all its forms)CEA glaucoma that have to result in a dogs death.  However owning a dog that is in acute pain that nothing can resolve because of a genetic condition does mean the only option is to end the dogs life & I wish to god there was a commerical firm rearching SHM as well as a couple of vet(both specializts)& a geneticist who are doing it on a shoestring.

I have owned a blind deaf dog & she lived until she was 19 on the otherhand my beautiful cavalier boy could have to be put down as a result on his genetic condition I sit here watching him like a hawk incase he stops being asymptomatic which he could at anytime & wish to god there was a DNA test to stop anyone else going through what I am at this time

Basically the AHT are not interested in the genetic side of SHM only in clients paying for their equipment to be used so that they can use it for more profitable projects

So instead of accusing me of being a child get off your very high horse & rasie money to get your non profit making  research  started, so you can show up the commerical company & get a 100% sccurate tests developed, just like some of the cavalier people are doing with little help from the top breeders & animal health charities

"there are no genetic conditions such as PRA(in all its forms)CEA glaucoma that have to result in a dogs death." says Moonmaiden.

Do you honestly believe that dogs don't suffer from sudden loss of vision? Mental pain or suffering is not to be measured.

Christine, I read your letter in one of the previous yearbooks. You have all my sympathy.

Dogs are very stoic when it comes to pain and disabilities but it does not alter the fact that they do feel things. Blindness is terrible in humans but can also be bad in dogs. I've had a couple of dogs which have gone blind later in life and both were so different in the way it affected them.

Mandy went blind slowly and really, she adapted as it progressed. She went for her walks, still running off lead in the field, with complete confidence. I always made sure she knew exactly where I was and at times when she was obviously lost I would run around the field to the place she was heading for so she always found me. She maintained her confidence to the day she died.

Katy on the other hand went blind in the matter of a few short months. She was diabetic and sugar cataracts built up on her eyes. She never had time to adapt and never did. Off lead walking worried her to the extent that she would just stop until I put the lead back on. She really never wanted to go out side the gate and was happier strolling around her garden.

I have always believed that the testing of the DNA was the way to go. If we can detect carriers we would really be in a position to eliminate these hereditary diseases. But should we? Look at it this way. There are so many hereditary diseases that it could well end up that the gene pool of dogs unaffected by anything is so small that the cure COULD be worse than the ailment. With 44000 Labradors born in just one year a small unaffected gene pool would be a disaster! We can screen for PRA, supposedly with 99.5% accuracy so does that make these clear dogs the dogs to use? What about the other diseases? Until we can screen for these we could be jumping out of the frying pan into the fire.

I feel we are in danger of seeing just one problem rather than the dog as a whole.

Regards, John

Yes John, I totally agree with you. A hypothetical question: if you had a bitch sired by a proven (PRA)carrier, would you breed from her?

No Northern Pack. I would not knowingly (at this time) breed from a known or suspected carrier. That's the short answer. (Notice the get out clause!) The longer answer I would give to your question is that if the DNA test finally achieves what we all want, and that is to be able to give us definitive answers, then it MAY be necessary in order to keep a viable gene pool in existence.

Take PRA as an example. At the moment we have a percentage of Labradors who develop PRA. The responsible breeders would not breed from these dogs! Apart from these there are direct offspring, a percentage of these will almost certainly be carriers and few breeders would countenance breeding from these, and rightly so. The problem comes from the third group of dogs, the undetected and unsuspected carriers. How many of these there are is totally unknown. These dogs are being bred from quite happily because no one knows there is a problem. (A friend who has been testing her Labs with us for more years than I can remember had a bitch fail to hereditary cataracts! it was one of the line she has built up through generations of breeding. The problem must have been there undetected for years!)

Now suppose for a minute that we have 100% DNA testing and that the results of the test are infallible. Who is to say just how bad the situation would be! Add to this, infallible testing for Cataracts, Glaucoma, OCD, Epilepsy, even HD! We could well be in a situation where we have so few totally clear dogs that it would be impossible to sustain the breed! And that could so easily happen! Check out Optigen site. They say that a carrier mated to a clear would result (on average) of a litter with 50% carriers and 50% clear. Take a litter size of 8 puppies this would mean 4 carriers and 4 clear puppies. Considering that we only started with one clear dog, after just one mating we now have 5 clear dogs!

Looked at like that, Yes, it is conceivable that I could breed from a carrier!

Regards, John

Hi John,

Excellent points, and well put (you're such an ickle star ;))

I think caring and responsible breeders already do everything they can to avoid hereditary defects and are always willing to take on board new tests etc. but eventually in many breeds removing every dog with any suspect gene could mean the end of a breed entirely - sort of throwing the baby out with the bath water :(

Hopefully it won't come to that for anyone's breed but if in future DNA etc testing does become 100% accurate on every conceivable problem then breeders will surely have to weigh up the seriousness of a certain condition in a prospective brood or stud against losing the many virtues it may have to offer to the gene pool.

Regards, Teri :)

ICKLE star??? I'm 6'2!

The thing is Teri, Labradors, taking one breed as an example, has a total of 6 hereditary eye defects tested for (including Abnormal pigment deposition which is under investigation). Over 44000 Labradors puppies were registered with the KC last plus of course many more which were not registered. How many stud dogs do you need to sustain this number of reproduction? How many dogs can you afford to take out of the breeding pool before the gene pool of the resultant puppies becomes unsustainably small?

Even with using carriers in the breeding pool, done carefully could eventually breed a genetic problem out!

Breeding is an extremely complex business which we have in the past approached in a seemingly haphazard manner. But are we wrong in what we do? In the USA many breeders will only breed their bitch to a champion. How many champions are there in Labradors? I don't know but I do wonder how restricted this would make the gene pool. (And supposed one or two of those champions is a carrier for some problem?) Some European countries only allow matings between dogs who have passed certain tests, some concerning temperament, some linked to hip and elbow scores. (And we all know how fallible hip scoring can be and I for one are not convinced that OCD is wholly hereditary) Breeding to "Flavour of the month" may well have been responsible for the spread in Glaucoma in Flatcoats! (My thoughts, not in any way an official theory.)

So where do we go? Your guess is as good as mine!

Best wishes, John

Glaucoma has occured in our breed, though it's mode of inheritance is unknown.  We know it is most likely genetic because of familial links with affecteds, but then dogs that ought to have been affected going by therir breeding weren't, so it is a mystery.  Sadly it is the Open Agnle form which comes on overnight with no predisposiition to test for.

We have had very few cases of PRA or PRA like affecteds, and sadly it seems the breed has at least two diferent forms of GPRA (different genes produging it) and also there was disagreement between eye specialists if the last 3 affected cases were PRA or not.  Not a lot of help in a numericallly small breed.

Now if all the progeny of said producer of these cases were removed, the breed could die out.  Unfortunately by the time it is known there may have been several generations of breeding, most of which will be unaffected or carriers.  One cannot throw the baby out with the bath water, especiqally when one isn't sure which water one si dealing with.

Now for the odd individual that is affected with PRA it is sad, but not life threatening, or from a practical angle expensive for the owner.  Sadly the cases (again fortunately very few, less than a dozen in the years since it was first noted in UK) of Glaucoma, almost always are very painful and expensive to treat, invariably ending up with the loss of the eyes.

It is quite interesting from the breed email list I am on  that Galucoma crops up much more often than PRA, mainly in the Puppy farmed stock which make up the large number of rescue dogs.

What I am trying to say that Genetic disease control is not simple, and that one cannot eliminate every dog that just might be a crrrier if one is to have any breeding stock left.  Every dog has bad genes.  Some will be passed on, and some wil not.  Breeders can only at best try to reduce the chances of prodcing affected puppies by studying their bred lines, and avoiding doubling up on ancestors which were known to produce the fault.  To totally remove whole sections of breeding stcok from the gene pool just reduces the gene pool even more giveing a chance for more bad things to come to the fore.

Just one thing to add to this debate. There was a case where a company doing DNA research for an eye condition, patented part of the genome. This meant that nobody, individual or company or the AHT could do any work on this disease. The breeders then had to go with the DNA test at great expense or use the tried and tested eye testing sessions. The DNA test subsequently turned out to be less than perfect and a lot of dogs passed were used for breeding and others failed turned out to be fine. Perhaps it is not the AHT or the fundraisers at fault but the way companies are racing to patent DNA sequences thus prohibiting this research.

M/Maiden I single handedly started the eye testing scheme for Labs in Spain by bringing Dr K Barnett over here to do it. Paid for all by myself, that means his return flight & all his expenses paid for by me from the moment he leaves his home till the moment he returns back to it. The last time he was here the people who had their dogs tested were charged only the fee he wanted with nothing on top.
I know I`ve done a lot more for my breed, Labradors in Spain, than a lot of folk would even dream of.

Can`t imagine were you got the idea I`m talking from my high horse from. My feet are very firmly placed on terra earth!!!!!!

Christine, Spain.

I am not allowed to comment on this subject any further

Oh dear, thats a shame.....

No hard feelings tho eh M/Maiden????? :D :D

Christine, Spain.

No comment I didn't think it was funny

Oooops, sorry M/Maide

Christine, Spain.

Moonmaiden, I have never know Admin stop anyone stating either what they know or even their opinion as long as the manner in which they state it fits within the TOS I think we all just have to learn to do that :)

its not fair to try to get a response from MM isabel,if she cant defend herself. think this subject has been done to death,we all know each others opinions,so shall we just leave it at that?

I think you have misunderstood my post, Michelled, it is not about the subject at all I am just reassuring Moonmaiden that she is free to "defend" her stance, whatever it is, as long as she conforms to the TOS.  My understanding of the TOS is that you are free to express your opinion but you do have to express in a way that is acceptable, in fact the TOS allow much more freedom for all of us as we should not be frighted of abuse when our opinions differ from the majority, hope that is clearer :)

whoops!!! yes i did misunderstand!!!sorry isabel!!!! :)
just goes to show though how easy it is to get hold of the wrong end of the stick on here!!!!!

No problem.
See, we're all getting the hang of this manners thing ;) :D