Collie eye anomaly in
Australian Shepherds

ABOUT 15 years ago, while I was a member of the Australian Shepherd Club of America's genetics committee, we began to get frequent reports of collie eye anomaly-affected Australian shepherd pups. One breeder donated an affected pair - a dog and a bitch. She also went public with the problem ... and was promptly pilloried!

We started using our regular column in the club magazine to educate people about collie eye anomaly (CEA). The disease was not recognised by ACVO as a breed problem. More than a few examiners were overlooking or mis-diagnosing the disease in our breed, particularly where the affected dogs had only minor choroidal hypoplasia, a thinning of the vascular tissue in the back of the eye which is a sign of CEA, along with optic disc coloboma and retinal dysplasia/detachment.

The "go normal" phenomenon further complicated the issue. As pigment fills in at the back of a young puppy's eye, it can obscure areas of choroidal hypoplasia, making the defect impossible to detect upon ophthalmic examination. A young pup would be diagnosed and, on re-examination a few weeks or months later, would show no sign of disease. Hence "go normal". This unfortunate bit of jargon has allowed more than one breeder in more than one breed to succumb to a massive case of what I call ostrich syndrome. Such self-deluded individuals would decide that affected dogs are "normal" and the disease went away, so they had no cause for concern. Interestingly, the two donated pups were both "go-normals".

The Australian Shepherd is gaining popularity in New Zealand, and there are now about 60-70 of the breed here.

One of the carrier bitch's normal daughters, by a stud proven not to be a carrier, also proved to be a carrier when bred to the affected stud. Most of the offspring up to this point had choroidal hypoplasia and a few also had unilateral optic disc colobomas. One puppy out of the carrier daughter's litter was totally blind due to retinal detachment. While all of this was happening, I ceased to hold any official capacity in the club. I kept gathering pedigrees and examination sheets. I had nearly 40 pedigrees with varying degrees of relationships, plus the test-mating data.

I went in search of an ACVO vet who might be interested in what I had and was directed to Lionel Rubin of the University of Pennsylvania.

I worked up genealogy charts for each affected dog's pedigree, cross-referenced to the other pedigrees. Dr. Rubin agreed that the trait appeared to be recessive. Using my gathered data, he wrote "Collie eye anomaly in Australian shepherd dogs" (Prog in Vet/Comparative Ophth Vol 1 No 2, pp105-108) and gave co-author credit to me and my other former club committee member.

The article not only made CEA in Aussies "real" in the world of veterinary medicine - it provoked a critical editorial in the subsequent issue of the journal attacking our semantics - the writer thought it should be "Australian shepherd eye anomaly." Dr Rubin rebutted with a piece that, if I remember correctly, was titled "A Rose by Any Other Name..." The semantic flap soon subsided and the article has since been cited in numerous other articles and books.

Back in the trenches the CEA problem persisted. At least two significant sires of the mid-1980s were carriers. The bulk of the affected animals were from show lines but a couple of pedigrees indicated that working lines were not immune.

At the time I didn't know if the paucity of data on working lines was because there actually was less CEA there or because most working breeders had their own case of ostrich syndrome, declaring "I don't have to worry about that genetics stuff, my dogs WORK."

Fortunately for them, time has proved CEA is a minor problem in working lines. Recently, however, there have been rumours of clandestine Border collie/Aussie crosses to produce better trial dogs. It will be interesting if CEA crops up in the suspect lines.

I tried to help breeders by setting up a pedigree analyses programme based on the data from the paper, plus things that came in subsequently. I continue to update my file as I gain new data. I roughed the programme out, then ran it by George Padgett at Michigan State University to make sure I didn't have any holes in my logic. Once the details were smoothed out I started rating pedigrees for dogs' owners and breeders.

I will not perform a pedigree analysis for someone who does not own a dog (or one of the dogs in a prospective cross). This is necessary to save myself unnecessary grief from outraged owners and breeders, as well as potential legal entanglements. The resulting rating indicates the probability that the particular pedigree might produce an affected individual and a carrier individual. That done, I factor in the "suspected carriers," the parents, offspring and full-siblings of proven carriers and give an additional rating (severe, moderate, slight or non-existent). With the rating I send information on the disease and how to interpret the rating. I also advise the owners on their options.

While I was working up the pedigree analysis programme, a bunch of northern California breeders decided they needed to do something. I worked with them to develop a test-breeding programme. They created an excellent set of forms to document the breeding, the litter produced, and the examination results on the pups.

These breeders also took a public stand. As a group, they purchased a full-page advertisement in the breed magazine, admitting they had produced CEA and listing the names of their carrier dogs. In a subsequent advertisement they told about the test-breeding they had done to clear their related stock. There is safety in numbers. While there was plenty of quiet grumbling about what they did, no one dared the kind of frontal assault suffered by the earlier breeder who donated the pups which formed the axis of our research breedings.

These good people proved invaluable in another way. When people call me about genetic problems in their Aussie Shepherds I'm "the expert," not a kindred spirit. A lot of folks I spoke to were suffering varying degrees of emotional distress. I called upon the breeder group to serve as a support net. Again, they came through.

CEA hasn't gone away - I got another pedigree to add to my list recently - but there appears to be a lot less of it out there. The knowledge that the disease is recessive and that one can test-breed to clear suspected carriers has resulted in more effective management of the disease by breeders, even though many wouldn't ever admit they'd managed their way out of it. Care with breeding is still vital.

Today, the incidence of the disease is down to about one percent, and carriers amount to about 10 -15 percent of total.

C.A. Sharp is editor of the Double Helix Network News. We are grateful for her kind permission to reprint this article.