Optigen & FN Misleading!

[hovis]

Sorry but I need a rant! 

I've just been browsing another forum where puppies are advertised for sale. Several 'breeders' are advertising puppies where the sire is optigen & FN clear and they go on to say that the puppies will never develop either of these diseases as a result. No mention is made of whether the dam is tested & her status as a result (I suspect not tested in some of the breeders cases). If the sire is clear & the dam is affected or a carrier then some of the puppies MAY also be affected/carriers. This is totally misleading to the purchasers of the puppies.  They will be thinking their puppy is clear of both diseases & potentially it may not be. Heaven knows the complicated genetic mess should they then decide to breed from their puppy in the future!

I assume it must be ignorance on theses particular breeders part but that is really no excuse. It makes it such hard work for the majority of responsible breeders who are doing so much postive work to ensure the future health of our breed.

Sorry, feel better for that rant now! 

[Cob-Web]

If the sire is clear, then even if the dam is affected, then the worst that can happen is that the pups will be carriers.


I know it is best practice to have both sire and dam tested, but perhaps they have used a clear sire in order to ensure that the pups won't be affected no matter what the status of the bitch 

[Phaedra]

A PRA and FN clear sire/dam will never have affected progeny. To get affected, a dog will needs to have one PRA/FN-gene from each parent and a clear dog has none to 'give'. He or she has two normal genes. 

Not even a clear X affected combination will result in any puppies developing either of the diseases in question. Clear X affected = 100 % carriers and carriers will never develop neither PRA nor FN. However, carriers must always be bred to clear dogs to avoid getting affected puppies.

My bitch had a litter in May. She is PRA and FN clear, so I bred her to a untested dog who I like a lot because of his temperament (very merry, retrieves birds spontanouesly), health (+ 10 years and still excellent eyes, ears, movement etc) and pedigree. He has not been used much at stud (despite being a show champion and game tracking champion) and I wanted to take the chance to have a litter by him. I knew that I would never have any affected puppies. There was eight puppies - 4+4.

I was going to test several puppies, but I persuaded the owner of the male to test him to se if we could exclude at least one of the tests. I knew before breeding my bitch that there was a very small risk that he should be PRA-affected, since his eyes was checked only weeks before he got ten years old. He turned out to be a carrier for PRA and clear for FN. I still had two puppy dogs at home and had them tested for PRA, to see if the result could help me make up my mind of which of them to keep. One was clear and the other was a carrier. I kept the clear one and sold the other to a family who wanted a dog for agility, game tracking, field work, obedience etc. He will never develop PRA and can be bred to a PRA clear bitch (but he is not going to be a stud dog). I kept a puppy bitch in co-ownership and she will be tested before being bred - if she turns out to be a suitable broad bitch from all other respects. She cannot be 'worse' than carrier.

I also have plans to mate my other bitch, who is PRA and FN clear to a male that has been tested carrier. I realise that I will need to test the puppies and this time I think I will do the entire litter. But I don't see the problem using carriers or untested dogs/bitches to clear
dogs/bitches. These tests are excellent to avoid breeding affected puppies. But if we should use only clear dogs/bitches for breeding, we will soon have a lot of other problems because, then we have to exclude 50 % of the population.

The puppies will never develop PRA or FN as long as one of the parents is clear.

 

[Jane S]

If the sire is clear & the dam is affected or a carrier then some of the puppies MAY also be affected/carriers. This is totally misleading to the purchasers of the puppies.  They will be thinking their puppy is clear of both diseases & potentially it may not be. Heaven knows the complicated genetic mess should they then decide to breed from their puppy in the future!

Well it that was true, then it would definitely be misleading but as others have said, as long as one parent is tested clear, no affected puppies can ever be produced. If the status of the bitch is unknown, then you're right that she could be a carrier and some carrier pups could be produced - this needs to be explained to potential purchasers and ideally registrations endorsed so pups are not bred from unless tested themselves. This is what responsible breeders are already doing when they mate tested carriers to tested clears. We need to breed from carriers to keep the gene pool as wide as possible and as long as this is done responsibly it really isn't a problem. This means using tested clear partners and endorsing registrations etc so that buyers understand that puppies from a clear x carrier mating should not be bred from without being tested themselves. Where it becomes a problem is if breeders are not testing their bitches and not explaining the implications of this to their buyers - sadly I do think this is happening as we've had several stud enquiries from breeders who don't see any need to test their own bitches

[hovis]

........but to say that 'carriers'  or for that matter 'clears' will NEVER develope PRA is inaccurate. They are at an extremely low risk of developing PRA (have a look at Optigen website) which is different to how some people are advertising and thus it is misleading. Theres also one person who advisertises that thinks the BVA Clear eye certificate is the optigen test and tells potential purchasers the same! 

[flossysmum]

I agree with the last posts, if 2 carriers are mated together, there will be some afflicted puppies and some carriers, if the sire has tested clear for PRA and FN, even if the dam was a carrier, the puppies will never be afflicted with PRA and FN as they need one PRA/FN gene from both parents and as phaedra says if one parent is clear, then there will be no PRA/FN gene to pass onto the puppies. It is wrong that some breeders think that the KC/BVA scheme test is an optigen test though.

[Jane S]

........but to say that 'carriers'  or for that matter 'clears' will NEVER develope PRA is inaccurate. They are at an extremely low risk of developing PRA (have a look at Optigen website) which is different to how some people are advertising and thus it is misleading.

Well you may not be able to blame the advertisers for that as it's Optigen which has recently changed their wording in relation to the prcd_PRA tests. We have Optigen prcd_PRA results (mutation test) which quite clearly state for a dog tested normal :Risk for developing PRA: This dog will never develop the prcd form of PRA (progressive rod-cone degeneration form of Progressive Retinal Atrophy). So far, the only inherited PRA disease known in dogs of your breed is the prcd form of PRA. They still use this kind of wording in relation to the FN test.

[Mazame]

I didn't have a look at the Optigen web site but has it happened that PRA-carrier tested dog developped PRA ??

[elaine.e]

I'm a bit confused having read this thread.

William's sire is a PRA carrier. He was tested when the test became available in the UK, which was just after William was born.

I don't know the status of William's dam. She had clear eye certs., so was clear at the age of 4 when bred from, but it was a one off litter, so there was little point in the owner getting her tested subsequently. (Also, I've lost contact with the breeder as she's moved, so can't ask how the dam is now).

One of William's sisters has been tested clear. As far as I know none of the rest of the litter have been tested and have not/will not be used for breeding.

My understanding is that even though William's sister tested clear, their dam could be either clear or affected, but not a carrier? If so, William could be clear, a carrier or affected? Is that correct?

I know I could have him tested, but as I don't generally spend much time worrying about something I can't alter, a large part of me would rather not know. It would be great if he tested clear or carrier, but if he was affected I would be worrying constantly about him.

[Cob-Web]

Each puppy in a litter has two copies of the gene, one from the dame and one the sire. Two mutated genes are required for the dog to develop the condition.

If the sire is a carrier, then he has one copy of the mutated gene, which he could pass onto any of the litter. 

If the dame hasn't been tested then she could be clear (no copies), a carrier (one copy) or affected (two copies).   The fact that one of Williams litter mates has been tested clear means that their dame must have had one normal gene - so she is either clear, or a carrier. 

If she is clear, then none of the litter can inherit the disease, but if she is a carrier, then some of the puppies may have inherited two copies of the mutated gene, one from each parent 

Does that help? 

[elaine.e]

Thankyou Cob-Web, that's very helpful. Maybe I should try and find where William's breeder moved to and ask if she knows anything further. She kept one of William's sisters, although not with any intention to breed, but simply because the puppy was so tiny in comparison to the others.