Posted: Mon Nov 08, 2010 10:20 pm Post subject: Cystinuria dna test
Ok... back to the minefield of tests available.
Cystinuria (dna test)
This one appears to have cropped up as a new one. I certainly hadnt spotted it before.
Has anyone heard of this test?, how big an issue is it in labradors?
I agree in an ideal world you would do all the tests, but I think when they are new ones it is all a bit "boggling" to do a test to then not know where to turn with your result.. agreeably ignorance is not the answer either.
Edited to add, I know what the condition is, but just wondered how many labs actually have it and therefore does it warrant yet another test potentially narrowing down the genepool?
The condition is basically urolithiasis, which is formation of calculi (stones) in the urinary tract. (A condition seen in humans whereby proteins/amino acids such as cystine, lysine, ornithine and arginine is present in the urine due to the impairment of the renal tubes.)
The condition although does cause pain for dogs to pass any "stones" can actually be treated and then maintained on a special diet. (edited due to post below from Jazz... I *had* thought it wouldnt be life threatening).The diet works be reducing the size of the stones and the animal should be monitored regularly. The diagnosis is made by way of urine testing AND an xray. The animal once the stones are small enough to be passed then go on to a maintenance diet. If the stones are causing an obstruction that is when surgery would be performed.
In my limited experience of stones - I believed it to be a bigger problem in cats and not dogs. Though I have seen dogs with stones.
(it is actually very interesting as to how the stones develop and the different types you can get....but then, that is just me?!!)
Thoughts please!
(edited to add description of the condition!)
Last edited by Marchstone on Tue Nov 09, 2010 2:38 pm; edited 2 times in total
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Not heard of this one either, but as several people have said in the past, just how far do you go with all these tests, if they go much further there`ll be at at least one dog in people`s kennels/homes with one of these problems that effectively removes them from the breeding program.
I think this is the one I saw asking for DNA samples for on the OFA site some time back. Just imagine if this were humans we were talking about, telling you that you must take a dozen DNA tests before you could have children!
They really seem to be in danger of inventing diseases in order to develop tests for them. Yes I've no doubt there are cases around, but I wont be testing for this any time soon.
I note Optigen have it on their list for Newfoundlands. Am I being cynical in thinking that as Newfoundlands are a numerically small breed, that the profit in testing them would not be great, so adding a numerically large breed such as Labradors into the test would make the test far more interesting to the testing people? (By the way, I also note that Optigen are NOT offering the test to Labradors. So I wonder who is??)
I have not come across this condition as regards labradors.
The main breed affected by this condition is the Dalmatian - where the frequency of the "normal" gene is believed to be almost zero.
I had a dalmation called Sam. He was affected by this very painful problem - which causes urinary stones. Despite constant veterinary treatment and strict diet we lost him at the age of just two
This Kennel Club report indicates the extent of the problem in dalmatians and should perhaps act as a warning to us of how far things can go if we don't take advantage of DNA testing for conditions known to exist within our own breed, and plan litters accordingly.
"[i]Registration of a Low Uric Acid Dalmatian Import from the USA
12-Jan-10
At its meeting on 5th January 2010, the Kennel Club General Committee accepted an application to register an imported Dalmatian produced from a breeding programme which was originated with an intentional Pointer/Dalmatian cross. This cross-breeding was carried out in the USA as part of a programme aimed at introducing the low (or normal) uric acid gene into the Dalmatian breed.
This decision is subject to certain conditions, which include the dog being examined by two Championship Show judges to confirm that its external appearance and characteristics are representative of the breed.
The decision taken by the General Committee is in line with the Kennel Club’s commitment to consider applications to register dogs from out-crossings and inter-variety matings if it is felt that to do so may present potential health and welfare benefits.
The Kennel Club consulted the Dalmatian breed clubs on this matter and their joint feedback was considered at length by the General Committee before arriving at this decision.
Background
It is believed that the Dalmatian breed is fixed for a recessive mutation of a gene that alters uric acid metabolism, resulting in increased urinary excretion of uric acid. This gene is not expressed in most other breeds of dog which excrete lower amounts of uric acid in their urine.
The use of a recently developed DNA test for this genetic mutation on Dalmatians in the USA has shown that the frequency of the normal gene is close to zero in the USA population of the breed. Similar DNA testing of the UK population has yet to be undertaken, but it is likely that a comparable scenario exists in the UK population of Dalmatians.
Some years ago in the USA, a cross-breeding was carried out between a Dalmatian and a Pointer with the intention of producing offspring that were low uric acid (LUA) excretors, because the Pointer used in the cross would not have carried the mutant gene. The offspring from this mating and their descendants have subsequently been back-crossed with purebred Dalmatians over many successive generations.
Decision
Recently, the Kennel Club received a proposal to register an imported LUA Dalmatian that is descended from the initial Pointer/Dalmatian cross. The outcross Pointer appears at least 13 generations back in the pedigree of the imported dog. In line with the general aim of the KC to help individual breeders and breed clubs to improve the health and welfare of future litters, the General Committee has agreed to register this imported LUA Dalmatian subject to confirmation from two championship Show judges that the imported dog’s external appearance and characteristics are representative of the breed.
The registration records of this dog and its descendants will be annotated by the KC’s normal asterisk system whereby the progeny of the first mating between the dog and a registered Dalmatian, the F1 progeny, will have their registrations annotated with three asterisks. Then, when F1 progeny are bred from, their progeny, the F2 progeny, will be annotated with two asterisks. F2 progeny will produce F3 progeny which will be registered with one asterisk. The F4 and subsequent generations will have no special annotation.
In addition to the above conditions the committee also agreed that the registrations of all progeny would be endorsed with the restriction ‘Not eligible for Export Pedigree’ for the next five years, and the owners would be required to submit a health report, to include BAER testing results, on all progeny in five years’ time.[/i"]
Do we really want to end up having to out-cross in a similar way because we have chosen to ignore genetic problems?
I have not come across this condition as regards labradors.
The main breed affected by this condition is the Dalmatian - where the frequency of the "normal" gene is believed to be almost zero.
I had a dalmation called Sam. He was affected by this very painful problem - which causes urinary stones. Despite constant veterinary treatment and strict diet we lost him at the age of just two
Im so sorry you lost your Sam, this must have been very distressing for you.
I *had* been under the impression it was a treatable condition that was successfull, rather than one that could lead to losing them in the nature you have.
I certainly dont want to rake over your feelings on this as understandably you will have emotions on the matter.
Thank you for taking the time to reply to my original post.
Last edited by Marchstone on Tue Nov 09, 2010 3:00 pm; edited 1 time in total
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I note Optigen have it on their list for Newfoundlands. Am I being cynical in thinking that as Newfoundlands are a numerically small breed, that the profit in testing them would not be great, so adding a numerically large breed such as Labradors into the test would make the test far more interesting to the testing people? (By the way, I also note that Optigen are NOT offering the test to Labradors. So I wonder who is??)
Looking through my notes on cystine urolthiasis, I will quote directly:
Cystine Urolothiasis occurs in dogs with an inherited defect in cystine metabolism, resulting in impaired re-absorption of the amino acid from the proximal tubule of the kidney and hence cystinuria. This leads to cystine urolith formation. Since cystine is relatively insoluble, particularly in acidic urine. Dissolution and prevention of reoccurence of cystine uroliths can be achieved through:
>Increasing water intake to increase urine volume.
>Reduction of dietary sodium to promote tubular reabsorption of cystine.
> Reduction of dietary protein to reduce cystine production and excretion
> Alkalinisation of urine (with bicrabonate or citrate) to increase cystine solubility.
> Administration of compounds such as D-penicillamine or 2-mercaptopropionylglycine (2-MPG) which converts cystine to a more solouble compound.
Also listed - Urate Uroliths - Dalmations., this type has the added implication of portosystemic shunts when heptaic conversion of uric acid to allanton is impaired. The notes outline a slightly different approach to the problem - still dietary but also lists surgical relief and administration of allopurinol which inhibits uric acid production.
I can therefore see the implication of portosystemic shunts make it far more of a serious condition - is then, the cystinuria the same for Labs? does it have the same potential for high risk?
As I had originally put in my first post (and now amended) I had thought this condition wasnt life threatening???
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The uric acid problem has long been with Dalmatians June, but not with Labradors. I'm sorry but this is a step too far. I will not test for a disease we do not have simply to make the genetic labs rich or to cover their research into the disease in other neumerically small breeds This test is not needed. We are in danger of people, me included, saying to hell with this, I'm not going to DNA test for anything! And that would be sad because I think there are things we should be testing for, including things like Epilepsy, which we do have in the breed, and for which at the moment we do not have a test for. Forget these rediculous tests and concentrate on the ones we do have a problem with.
As I had originally put in my first post (and now amended) I had thought this condition wasnt life threatening???
It's not life threatening Heidi, The Dalmatian people have been living with it for years. Diet is important with it though and through diet, almost all cases can live a perfectly normal life. Certainly I never had a problem with my Dalmatian.
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