Another eye issue or..

[Journey]

If it's not definitive, how can they say a DNA test is available? Or is this along the lines EOAD?

321406.full.pdf

[Mark Billadeau]

Where in the linked article do the authors state there is a test for this “risk genotype” mutation?

 

From the discussion section:

“Although developing a test for the OLFML3 mutation would allow breeders to select against homozygotes and heterozygotes to decrease the prevalence of the risk genotype for severe goniodysgenesis, it is important not to reduce the breeding pool too much because of the risk of other recessive conditions resulting from homozygosity for alleles that are identical by descent.”

 

There would be no problem developing a dna test for this genotype (or any other genotype).  Buyer beware of what the genetic test results mean.

[Mark Billadeau]

Ever notice how some multivitamins add new ingredients every time there is a new study (reported on the news) showing correlation (correlation not causation) between some compound and a health benefit?

Get ready for new genetic tests for every/any genetic mutation correlated to a disease.  Developing tests for genetic mutations is easy, proving a mutation is causal for a disease takes time (months/years) and effort.

[Journey]

They don't, not that I could find. How can they link two issue to one gene too? 

 

I'm not used to the new boards! Thanks for the info! I couldn't find anything else other than this article.

13 minutes ago, Mark Billadeau said:

Where in the linked article do the authors state there is a test for this “risk genotype” mutation?

 

From the discussion section:

“Although developing a test for the OLFML3 mutation would allow breeders to select against homozygotes and heterozygotes to decrease the prevalence of the risk genotype for severe goniodysgenesis, it is important not to reduce the breeding pool too much because of the risk of other recessive conditions resulting from homozygosity for alleles that are identical by descent.”

 

There would be no problem developing a dna test for this genotype (or any other genotype).  Buyer beware of what the genetic test results mean.

 

[Mark Billadeau]

From the intro:

“Primary glaucoma is a condition in which increased ocular pressure damages the retinal ganglion, leading to blindness (reviewed in [2]). In domesticated dogs (Canis lupus familiaris) it can be preceded by goniodysgenesis (also known as mesodermal dysgenesis), a developmental abnormality of the eye characterised by narrowing or closure of the iridocorneal angle (ICA) through which the aqueous humour drains.”

goniodysgenesis CAN precede glaucoma

in the middle of the article the authors discuss how goniodysgenesis can predispose dogs to developing glaucoma but there are likely other genetic and environmental factors that influence the development of glaucoma.

 

from the discussion

“We propose that the p.Arg197Gln mutation in Border Collies is responsible for the presence of severe goniodysgenesis predisposing to glaucoma in homozygous animals.”

[GentleLake]

As an aside, I notice they've referred to the Anadune database. Does this mean this is primarily a KC Barbie collie bred issue? Has it been identified in working border collie populations as well?

My memory fails me at the moment, but wasn't there another genetic issue that surfaced in Australian dogs and was mostly limited to the KC fake border collies?

[Mark Billadeau]

The mutation you’re likely thinking of is TNS; a low frequency of carriers have been identified in working bred dogs.

 

When the allele frequency in a gene pool is low that genetic mutation may not be visible; known due to dogs being affected with the disease caused by the mutation.  The mutation is still present in the gene pool and can become evident with in-breeding.

How can the frequency of this mutation (not yet proven to cause a disease) be known in populations not part of this study when no test has been developed for this mutation?

[Journey]

Ok, I'm following so far, I hope. They found a disease in a few dogs, found a mutation, but there's no correlation as some with the mutation didn't get the disease. So there's a predisposition/assumption for this mutation to cause the disease but no test to prove it out as some with the mutation do not have the disease.

[GentleLake]

Thanks for jogging my memory about TNS, Mark.

Of course I'm aware that uncommon mutations may not result in affected dogs in large populations and that inbreeding can concentrate and reveal them.

You remark that "no test has been developed for this mutation." How then can breeders like Anadune (and I'd guess others, though I don't care to search further) make the claim that their dogs have "passed"? Are these fake certifications?

"Wildblue Soulsearch at Anadune...Goniodysgenesis passed." (https://www.anadune.com/dogs/fea.html)

"Anadune Chosen One...Goniodysgenesis passed." (https://www.anadune.com/dogs/buffy.html)

And others . . .

 

 

[Mark Billadeau]

I’m guessing you did not read the article 

 

From the article on how the phenotype of the dogs was established

“Goniodysgenesis was diagnosed by examination of the eyes with gonioscopy when the status of the drainage angle and the pectinate ligament fibres that span it was assessed.”

 

the article was on finding a genetic marker correlated with dogs assigned with the phenotype of goniodysgenesis