US Eurasiers with unusual hereditary disease

 Already in the middle of 2007 a US breeder reported about the coming up of the (up to now) unusual hereditary disease "epidermolyis bullosa" – or shortly – EB.

 Some words to the symptoms :
Just some days after the birth the puppies will not grow as usual. The pads and thin parts of the skin will blister. Blains may build up on the oral mucosa,  hindering the puppy to suck. The nails may fall out. These puppies will not survive.

 These symptoms originate in a reduced and respectively not existing bonding capacity of the epidermis to the lower tissue. This effect is of genetic origin. Hence even microscopic  lesions result in an ablation of these layers.
Because of the fact that even normal walking leads to micro lesions the affected area will never heal resulting in permanent danger of infection. The affected puppies suffer incredible pain and there is the danger that they die because of secondary infections.

To prevent this suffering the Vet from the state university Pennsylvania, that handles this EB case gives the advice to euthanize the poor creatures.
The mentioned vet is about to develop a test, to find out the dogs that bequeath this disease. However the research for such a test may last several years.
But how should the Eurasier community now handle this case? To find out an  answer to this question, it is necessary to have a closer look to the heritance of this disease.

 As most of the readers may know, the genetic information is located in the chromosomes. Dogs have (like humans) in the cytoblasts of every cell at a time a double set of chromosomes – only the reproduction cells have one set.
On the paired chromosomes related parts of the chromosomes are responsible for the forming of a certain attribute of the creature. This parts are called allels.
The corresponding parts may not be identical- this is the heterocygotic case – if they are identical, we have the homocygotical case.

The disease EB now materializes in this case when both genes are abnormal.
A puppy carrying only one abnormal gene isn’t visible ill because the sane allel will clear the abnormal one.
Because of the fact that exactly one of these two genes comes from the mother and the other one comes from the father, the chance, that a puppy really is diseased with EB comes up only in the case when  the father as well as the mother are carrier of the bad gene.

According Mendel’s rules this results in a statistical probability of 25% for a diseased puppy (which will not survive), 50% of a puppy that is visibly sane but a carrier of the bad gene and 25% for a sane puppy – a non-carrier.

One can see, if one keeps in mind that the really diseased puppies will not survive and hence are not available for the further development of the population, that in average there are twice as much carriers as sane non-carriers – in case both parents were carriers.

The inheritance of EB is comparable to another hereditary disease of our Eurasiers – distichiasis. Patella and HD are not directly comparable because in this cases the impact of the environment may be decisive –although this impact is metrically hard to handle. Furthermore are this hereditary diseases not lethal.

 Even though only few vets are able to diagnose EB the assumption seems to be justified, that EB is still a rare disease in the Eurasier population, because the puppy death rate in the population isn’t dramatic and not every dead puppy dies because of EB.

 So that EB does not develop in about 10 or 15 years to a new standard hereditary disease like HD or DI, that more or less can be controlled but never will be eliminated, activities are indicated. All the more as this hereditary disease unlike HD or DI is lethal for the affected puppies.

The most horrible scenario comes up, if one assumes that somewhere along the way all living Eurasiers are carriers of the defect gene. Then in average 25 % of all puppies are doomed.

I see 2 decisive reasons, that necessitate a concentrated reaction of all breeders. 

What are the possible reactions?

Do nothing. Continue breeding as usual, wait for the availability of a test for EB.

Basically I think that it is obvious, that an identified carrier has to stop breeding. It is the least that can be done.

If there arrived only a little bit of what we call "cultural evolution" in the minds of the responsible persons, the possibilities 1 and 2 drop out. The first alternative simply ignores the above mentioned effect of  unchecked spreading of the gene over the population- with all its risks.
The second one I simply call an evil animal experiment. Finally it aims to get doomed puppies because this is the only way to find out another carrier.

Only the imagination that someone expects his female dog of carrying out a litter in the hope to get at least one doomed puppy nauseates me.

The reader may judge by himself, what statistics tells us.
Assumption: The female is a carrier of the bad Gene. The sir is the candidate to find out, whether he is a carrier or not. The table shows the probability, depending on size of the litter, to get at least one really doomed puppy if the sir is really a carrier. (Remember: Only the appearance of at least one doomed puppy leads to the 100% conclusion that the sir is really a carrier)

Size of litter     probability for at least one doomed puppy 

1       25%

2       43%

3       57%

4       68%

5       76%

6       82%

7       86%

8       90%

9       93%

10   94%

The following table shows the probability having not even one carrier in the litter if the sir himself is no carrier. In this case none of the puppies is visibly ill because each of them has at least one sane allel.

Size of litter            probability having not even one carrier

1                               50%

2                               25%

3                               13%

4                               6%

5                               3%

6                               2%

7                               1%

     >8                   <1%

I think these values are self explanatory. The chances to get completely sane dogs are much lower that the ones to find out a carrier.

The miserable handling in the sense of "it is only dog" should belong to the past and substituted by  methods showing that the people that are about to lead our breed into a good future have an indicated respect for creatures.

 The third alternative is of course not the easiest one, it calls for a handling controlled by respect for the dogs by all concerned persons – with all its possible consequences.
Every argument dealing with economics has to be refused.
I really hope, that the responsible persons of ALL Eurasier clubs bring themselves to a common solution. Up to now there were only actions of appeasement aiming to avoid to publish this problem. Such a policy must not be accepted and every responsible breeder must ask himself whether he is willing to accept such a policy.
It is not allowed to centre the reputation of the breed or even of certain persons. The duty of taking care for the breed as for the single breeder necessitates a united effort of the Eurasier community.

It is very deplorable that the mentioned US breeder had another litter with the same mother (5 sane puppies – no EB). Let’s have a closer look to this case with the help of the above mentioned tables of probabilities. The adjudgement for this case will be disastrous.

With the assumption that the sir was indeed an EB carrier, we get still a probability of 24 % for having not even one doomed puppy in the litter.  (table 1, case 5 puppies, subtract the given value from 100%)

With the assumption that the sir was NOT an EB carrier we find in table 2 the chance to get not even one EB carrier in the litter lower than 3 %.

The production of carriers has started!

We see how probable it is, that the genes gets spread.

There is the only hope that this absence could be cleared. A first failure of the responsible persons got reality. The justification, one is waiting for the test, is to recognize as an antagonism  even for laities.
Why wait for a test if even today one can say that there are at least two carriers in US? The test, as soon as  available, can not find out more than whether the dog is a carrier or not.
Is it an indication that one intends, even if the test is available, not to stop the carriers from breeding?
I hope that the responsible persons will come to a clear and really indicated conclusion

Author : J Butcher - Germany

 

 

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