Collie Eye Anomoly

[rodger]

I am planning to purchase a border collie for a companion for my daughter from a local rancher who uses the mother and father as working/herding dogs. After looking at the puppies, the one I am partial to is much more mellow than the rest of her siblings, and has one eye which is blue, the other is brown. All of the other puppies have two brown eyes. I was wondering if anyone knows if an eye discolloration such as this is any indication of possible eye problems which I understand collies can be predisposed to.

[dot me not]

Sounds like the pup you like just happens to have a blue eye. It is pretty common in border collies, especially when there is a lot of white facial markings. They can have one blue eye or two and sometimes there is only a partial blue eye. Color will have nothing to do with inherited eye defects.

I once heard an older man say not to worry about the color of the eye(s), but instead to be concerned with what's between the eyes. I never see a blue eyed dog without thinking about that advice.

Lydia

[Laura]

Hi,

 

CEA can be checked for in puppies ideally around the age of 6 weeks old, by a canine opthamologist. Ask if the breeder will have this done. The color of the eyes does not have anything to do with it.

 

Laura

[Pam Wolf]

Sorry, Laura, but the vets have been telling me 8 weeks for the last several years. It causes some problems as many breeders want to get rid of pups prior to that age. With the high incidence of CEA in the breed today, my feelings are that all litters should be checked.

 

Pam

[Laura]

Dr. Ackland (spelling?) told me that 6 weeks is the IDEAL age for checking the eyes for CEA. He is a renowned expert. I am aware that some eye clinics won't see puppies before 8 weeks of age. Fortunatley, the ones around here will.

 

The issue is unrelated to when pups should be going to new homes. The concern is the stage of the development of the eye.

 

Laura

[Pam Wolf]

I heard the 6 weeks years ago and it would be nice, but K State, MU and the Vet Specialists in KC all want them at 8 weeks. The reasons for this I can't say, but I did prefer it at 6 weeks.

 

Pam

[trailrider]

I have been doing eye checks on rough collies for 30 years. The specialists all say 6 to 7 weeks will give the most accurate observation. A dog with mild chorioretinal change can be developing the pigmentation by 8 weeks, and thus give a false security as to the genetics of that particular dog. Although such a result will not alter the health and vision of the dog, it is important for breeding decisions. Collie eye anomaly is in the genetic makeup of the majority of rough collies.

 

[This message has been edited by trailrider (edited 05-27-2002).]

[clarkshas]

My girl has a blue eye. She's almost 4 and no problems. My Vet did say there can be some risk that this eye is more prone to eye problems later in life (jut as a light skinned person can be more prone to skin problems with ongoing exposure to the sun). That's a bit wait and see I guess. She's the best little dog and her eye is gorgeous. I wouldn't trade it or her for anything.

Sharon

[Bill Fosher]

Pam,

 

You say the incidence of CEA is high -- the statistics that I have seen is that about 2 percent of the dogs in the breed are effected. That doesn't strike me as terribly high.

 

It's something worth paying attention to, surely, but I don't think it's much of a cause for alarm.

 

 

 

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Bill Fosher

Surry, NH

[Guest PrairieFire]

I agree with Bill, like many "Border Collie Diseases and Traits" - genetic or otherwise - some of the hoopla is simply conformation people finding ways to "prove" thier dogs...since they can't do it on the trial field or farm, they have to emphasize "disease-free and genetically sound" - which also requires an equal emphasis on having a "bunch" of unsound dogs - tempermentally, genetically, or otherwise.

 

Since CEA is easy to test for, and easy to predict, however, every litter and every dog SHOULD be checked...it's easy and simple...

 

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Bill Gary

Kensmuir, Working Stockdog Center

River Falls, WI

715.426.9877

www.kensmuir.com

[Tassie]

First post from a newcomer. For what it's worth, my new little BC bitch is one of 4.They were all eye tested at 6 weeks - seems to be the normal age in Australia. 2 girls, including mine, tested positive for mild CEA - choroidal hypoplasia. They may 'go normal' by about 12 -14 weeks. My girl was not going to be bred from anyway, so it's not a problem for me, as she herself will most likely not have any problems according to the eye specialist. The other 2 pups had clear eyes, including one girl with a blue eye - so I guess that helps to answer the CEA question about blue eyes. Incidentally, my girl's parents were both clear eyes, but one grandparent was a CEA carrier.

[Bill Fosher]

Tassie,

 

If there were CEA affected pups in the litter, not only was one of the grandparents a CEA carrier, so were *both* parents. They don't have the disease themselves because they carry just one copy of the CEA gene. That means that each pup in the litter got at least one copy of the gene. All the pups in that litter are carriers or affected.

 

 

 

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Bill Fosher

Surry, NH

[CMalazdrewich]

Bill said:

"All the pups in that litter are carriers or affected."

 

Perhaps, but not necessarily so - one or both of the ophthalmologically normal pups could be truly normal non-carriers. Unless I've fallen behind in my reading, CEA is generally accepted to be transmitted via an autosomal recessive mode of inheritance. A review of Mendelian genetics is beyond the scope of this discussion, but in very simple terms this means that dogs afflicted with CEA carry two defective copies of the gene (aa) while carriers of the condition carry only one defective copy (Aa). Normal non-carriers carry two normal copies of the gene (AA). As long as a normal copy of the gene is present, no eye abnormalities occur.

 

Since the litter discussed above includes affected puppies, we know that each parent dog is either a carrier or CEA-affected. Assuming that both are carriers, each parent has one normal copy of the gene and one defective copy. Which way the pups turn out depends on how many copies of the defective gene they inherit: 0, 1, or 2.

 

2 defective genes (aa) = CEA-affected

1 defective gene (Aa) = eyes are normal, but pup is a carrier of the condition

2 normal genes (AA) = eyes are normal, and pup is NOT a carrier

 

It is possible that both of the unaffected pups in the litter are carriers. Only genetic testing or test-breedings with other known carriers could establish that for sure - I don't know whether such a test is available for this particular condition. Statistically speaking, however, if the same bitch and dog were crossed repeatedly, about 25% of their offspring should be ophthalmologically normal non-carriers that would not be capable of passing along the causative gene. If one of the parents is CEA-affected rather than a carrier, however, then Bill's statement is correct and all of the pups are either affected or carriers.

 

Have a good weekend!

 

 

 

[This message has been edited by CMalazdrewich (edited 06-08-2002).]

[Bill Fosher]

I stand corrected. You're absolutely right that the ones that are normal may be unaffected unless one or both parents are affected.

 

Thanks for pointing out my mistake.

 

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Bill Fosher

Surry, NH

 

 

 

[This message has been edited by Bill Fosher (edited 06-09-2002).]

[Bill Fosher]

By the way, there is a linked-marker DNA test on the horizon that would tell whether a dog is a CEA carrier without test breedings. The American Border Collie Association is funding the research.

 

Unfortunately, the test is not ready yet, so for the time being we have to rely on pedigree research, test breedings, and on breeders having an understanding of the disease and how to manage it in the population of working dogs where genetic diversity is so critical.

 

Click on the "health and genetics" link of the ABCA's website: http://www.americanbordercollie.org for a thorough discussion of the genetics of the disease and the outlook.

 

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Bill Fosher

Surry, NH

[trailrider]

I thought the DNA testing for carrier status in several dog breeds was being done on PRA - not connected to CEA. Any info on that? Also, in the last thinty years, all that I have read about Rough Collies and related other breeds gave me the conclusion that Collie Eye Anomaly is not a simple gene - but a complex of several carrier genes. Any newer info that I can read? Thanks.

[Guest C Denise Wall]

trailrider,

 

Bill wrote:

 

>Click on the "health and genetics" link of the ABCA's website: http://www.americanbordercollie.org for a thorough discussion of the genetics of the disease and the outlook.<

 

Try that link for an overview on both CEA and PRA in border collies. I can tell you first hand it's not old info.

 

Denise

[trailrider]

Thanks - but I read that already. I just wondered if there were more research, or surveys on the details. I`m familiar with the good doctor that is doing so much eye research.

[trailrider]

Well, here is an article, and a response from the person who heads the health and genetics for the Collie Club of America.

 

 

Support CEA Research!

 

Dr. Gregory Acland of Cornell University's Baker Health Institute is

 

conducting research on Collie Eye Anomaly, a

genetically recessive, sometimes blinding, eye defect. The gene is

the same in Collies and Border Collies. Test matings with

Australian Shepherds and Shetland Sheepdogs have yet to occur, but

it is probable that the disease in those breeds is also

caused by the same gene. Based on recent CERF statistics, it is

probable that somewhere between 10% and 15% of Aussies

are CEA carriers.

 

Dr. Acland's goal is to develop a DNA gene test for CEA. With such a

 

test the status (normal, carrier or affected) of all

breeding stock could be determined. With such a test CEA-affected

puppies need never be produced again. If the status of

carriers were known, they could be bred only to non-carriers,

preserving their positive traits while avoiding CEA in pups.

 

I strongly urge all of you to support this research. Urge your clubs

 

to support it also. There are three ways you can do this.

 

1.If you have a CEA-affected or carrier dog or it?s near relatives

 

(parents, grandparents, offspring or siblings), please

be willing to donate a blood sample for DNA testing. Cornell

will provide the kit and most vets are willing to donate the

blood draw for research.

2.If you have an intact CEA-affected Aussie or Sheltie, especially

 

a male, please consider making it available to Dr.

Acland on a loan or through donation so it can be used for test

matings with CEA-affected Collies and Border Collies.

3.Donate funds toward this research. DNA tests are expensive to

develop. Right now only the working Border Collie

clubs have committed to support this research. They and Dr.

Acland deserve the support of all people and clubs with

CEA-affected breeds.

 

If you have CEA affected dogs or their relatives, please contact

C.A. Sharp at the address/phone numbers below. Send your

tax deductible donations to:

 

United States Border Collie Club, Inc.

Davida Hall, Treasurer

12813 Maple Street

Silver Spring MD 20904-3004

 

 

I am surprised that Greg is saying that. We have found that CEA is not just

a simple recessive. There are modifiers that will determine if the problem

is expressed, how it is expressed and the degree of expression. For example:

a collie puppy that carries the inheritance for Coloboma will show up normal

if there is no C change. We do know that a true normal is Dominant. I have

known of only 1 true normal in Collies. He could be bred to a CEA blind and

all the puppies would be normal.

Because Collie people have been so diligent in their testing, the

number of CEA blind or badly affected collies is almost non existent. We do

have many clear collies now too. However, because of the testing, collie

puppies must be checked young ( even at 4-6 weeks) because many mildly

affected puppies are normal at 12 weeks of age.

I hope this helps.

 

Dr. Richard Donavan started checking Collie eyes in the 1950s. He

was the vet. that was associated with the Retina Foundation and in fact had a

kennel of badly affected Collies. It was with this kennel that the work on

repairing torn retinas for humans was started. Most of us that started

working with Dr. Donavan in the early 60's now feel more secure breeding dogs

with slight C. Change and no Staphloma, and no Retinal Vascular Disease than

we do to dogs that are clear. A Dog that is clear, could be carrying the

Staphloma, but because of no C change, it would not be expressed. A Dog that

has C change but no staph, will not usually produce staph or detachments.

This is the way most of us have improved the breeds eye ratings. There are

many cases of stud dogs that are slightly affected with only C change

improving the eye ratings of puppies from severely affected bitches. Most

knowledgeable canine ophthalmologists that have dealt with collies admit that

there are modifiers that influence the eye ratings.

Barbara Schwartz

 

 

 

[This message has been edited by trailrider (edited 06-12-2002).]

[Guest C Denise Wall]

trailrider,

 

Yes, the CEA modifier is well known to those doing the research in border collies. In border collies, we are not in as desperate a state as the people in rough collies once were. Collie people had no choice but to breed lesser affected dogs, making the modifier status much more important than the presence of the actual CEA gene since they almost all had two copies of the bad gene anyway.

 

With only about a 2.5% affected rate in our breed, the goal is to breed through the CEA problem by using the DNA test to assure that at least one of an eye tested, unaffected mating pair is genetically clear, that is, carries no bad copies of the main CEA gene. That way no affected puppies would be produced even if the other non DNA tested dog is a carrier. It's not important what the modifier status is if the CEA gene is not present, or not present in two copies, to start with. Therefore we have not focused much attention on the CEA modifier gene(s).

 

Test breedings have determined the CEA gene is the same in collies, aussies and border collies. That means the CEA DNA test, which will more than likely be a linker test at first, will be useful for all these affected breeds. The last I heard from Greg was that the test would be available sometime in 2003.

 

Please feel free to ask any further questions you might have.

 

C Denise Wall, PhD

ABCA Heath and Genetics Committee Member

[Bill Fosher]

Trailrider,

 

Maybe Eileen Stein can chime in on this, but I believe that donations to support CEA research would be better sent to the ABCA, which is funding it. But perhaps the USBCC has some means to see the money to the proper place.

 

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Bill Fosher

Surry, NH

[trailrider]

Denise: I am curious as to how we know they are modifier genes, and not separate influencing genes that will cause problems even when we finally eliminate the basic gene that they are looking for right now? I`ve had Rough Collies for 35 years, and Border Collies for only 20 years, but I am always overly interested in research, even though we may not accomplish all we want. We have cea genes in the Rough Collies, that`s for sure.

 

 

Bill: I would only donate to the ABCA where I am a lifetime member. I just quoted those articles for reference.

[trailrider]

I just got an e mail from Greg Aucland who said that the inheritance mode of

CEA is more complicated than a simple recessive.

 

 

This was a message from my friend - again.

[Guest C Denise Wall]

trailrider,

 

It is more complicated than simple recessive if you include the modifier effects. However, as far as I know, there is one basic CEA gene that must be present in two copies for CEA to be expressed in any form or severity. Hopefully it's this key gene we will have a DNA test for since it's the simplest and most straightforward way to control the disease.

 

I will write Greg to make sure something new has not come up that I'm unaware of. We do get reports on the progress of the research and I've heard nothing about more than one CEA gene.

 

You wrote:

 

"We do know that a true normal is Dominant. I have

known of only 1 true normal in Collies. He could be bred to a CEA blind and

all the puppies would be normal."

 

This is consistent with an autosomal recessive mutation as has been claimed for the main CEA gene.

 

Denise