Goniodysgenesis and glaucoma in Border Collie

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A DNA test for Goniodysgenesis and glaucoma in Border Collies will be available from the Animal Health Trust DNA testing service from the 25th of February 2019

Border CollieA genetic variant in the gene OLFML3 has recently been reported to be a candidate for pectinate ligament abnormality (PLA), a form of goniodysgenesis, and primary closed angle glaucoma (PCAG) in the Border Collie. The study has been presented at a conference and published online without peer review (1, 2). In 2018 the Animal Health Trust undertook its own study to i) assess the association of the reported OLFML3 variant with PLA and PCAG in Border Collies, ii) to estimate the frequency of the variant within the United Kingdom Border Collie population and iii) to assess whether the variant is present in dogs with PLA and PCAG in other breeds.

In our study we screened 106 Border Collies for the OLFML3 variant and our data confirmed association of the OLFML3 variant with PLA and PCAG in Border Collies from the United Kingdom. We are confident that DNA testing for the variant and selective breeding will result in a reduction of PLA and PCAG prevalence in the breed.

Our data are consistent with the variant having an autosomal recessive mode of inheritance. To reduce the risk of breeding Border Collies that will develop PCAG we advise, therefore, that all Border Collies are tested for the OLFML3 prior to breeding and that at least one parent of every mating is clear of the mutation.

Border Collie WeaveWe identified a very small number of Border Collies that did not carry the OLFM3 variant but that were affected by either PLA affecting > 20 % of the iridocorneal angle of one or both eyes, or PCAG. It remains a possibility, therefore, that additional variants segregate in the Border Collie that are associated with PLA and/or PCAG. We therefore recommend that all Border Collies have their eyes examined by a veterinary ophthalmologist prior to breeding, in addition to having a DNA test.

In our study cohort of Border Collies form the UK the frequency of the OLFML3 variant was 0.044. We did not identify dogs of any other breeds that carried the OLFM3 variant, indicating this DNA test is only relevant to Border Collies; we therefore do not advise using it for any other breeds.

 What does the DNA test tell me?

The DNA test for Goniodysgenesis and glaucoma identifies if your dog is clear of the OLMF3 mutation, is a carrier of the OLMF3 mutation or has two copies of the OLMF3 mutation.

To reduce the risk of breeding Border Collies that will develop PCAG we advise, therefore, that all Border Collies are tested for the OLFML3 prior to breeding and that at least one parent of every mating is clear of the mutation.

CLEAR: These dogs have two copies of the normal gene and will not develop Goniodysgenesis and glaucomaas a result of the OLMF3 mutation we are testing for, although we cannot exclude the possibility that they might develop a similar condition due to other causes or the effect of other, unidentified mutations

CARRIER: These dogs have one copy of the OLMF3 mutation and one normal copy of DNA. These dogs will not develop Goniodysgenesis and glaucoma themselves as a result of the OLMF3 mutation but they will pass the mutation on to approximately 50% of their offspring.

AFFECTED: These dogs have two copies of the OLMF3 mutation and will have Goniodysgenesis and glaucoma caused by this mutation.

We cannot exclude the possibility that some dogs might develop a similar condition due to other mutations they might carry that are not detected by this test.
We identified a very small number of Border Collies that did not carry the OLFM3 variant but that were affected by either PLA affecting > 20 % of the iridocorneal angle of one or both eyes, or PCAG. It remains a possibility, therefore, that additional variants segregate in the Border Collie that are associated with PLA and/or PCAG. We therefore recommend that all Border Collies have their eyes examined by a veterinary ophthalmologist prior to breeding, in addition to having a DNA test.

Breeding Advice

We recommend that for the first few generations after the development of a DNA test that carriers are still bred with to avoid reducing genetic diversity. Please see our report regarding breeding with carriers for further info.

Dogs carrying this mutation can be breed from safely to avoid producing affected puppies. Carriers of the mutation should be mated to dogs that have a clear result; such a mating will not produce any puppies affected the OLMF3 mutation

On average, 50% of such a litter will be clear and 50% carriers; there can be no affected dogs produced from such a mating. The distribution does vary from litter to litter.

Pups which will be used for breeding can themselves be DNA tested to determine whether they are clear or carriers of the OLMF3 mutation.

For more information please contact us and we will be happy to deal with your enquiry.

1.Pugh CA. A mutation in Olfactomedin-like 3 (OLFML3) is a candidate for severe goniodysgenesis and glaucoma in Border Collies. Companion Animal Genetic Health 2018.

2. Pugh CA, Farrell LL, Carlisle AJ, et al. Arginine to glutamine mutation in olfactomedin-like 3 (OLFML3) is a candidate for severe goniodysgenesis and glaucoma in the Border Collie dog breed. bioRxiv. https://www.biorxiv.org/content/early/2018/05/14/321406, 2018.