Goniodysgenesis is a genetic disorder that causes the space behind the eye to not fully develop. This eventually causes a buildup in pressure behind the eye. The pressure is is very painful and, if left untreated, blindness occurs. Typically, due to the extreme pain and eventual blindness, the eye is surgically removed. Goniodysgenesis is the genetically-caused version of glaucoma. When talking about inherited glaucoma, goniodysgenesis and glaucoma can be used interchangeably.
Most forms of glaucoma can be placed into two categories: primary and secondary. The term primary glaucoma is used to describe glaucoma caused by an inherited physical or physiological trait that an animal has genetically inherited. These traits are generally recessive (needing two copies of the mutated gene) and are passed down from one generation to the next.
Secondary glaucoma is a term that refers to when the disease is triggered by something other than genetics. Things like eye trauma can cause bleeding, swelling, and inflammation to occur. As the eye heals, scar tissue may form. This impacts the normal drainage of fluid which then results in increased pressure in the eye.
More than 40 dog breeds are genetically predisposed to goniodysgenesis, including:
- Flatcoated Retriever
- Welsh Springer Spaniel
- Cocker Spaniel
- American Cocker Spaniel
- English Springer Spaniel
- Basset Hound
- Border Collie
- Golden Retriever
- Dandie Dinmont Terrier
Unfortunately, a majority of dogs with glaucoma will become blind in the affected eye within the first year, regardless of medical or surgical treatment.
Symptoms associated with primary glaucoma include:
- severe pain
- sensitivity to light
- winking spasms
- raised third eyelid
- watery eyes
- behavioral changes (hiding, refusing to eat)
- red eyes
- dilated pupils
- dog wincing when head is touched
- and/or eye appears to have fallen into the socket.
The discovery of a genetic variant on the OLFML3 gene was performed at the Roslin Institute, the University of Edinburgh, and the Mater Research Institute-UQ, Brisbane, Australia. The individuals credited for this work are Kim M Summers, Ailsa J Carlisle, Carys A Pugh and Lindsay L Farrell. Animal Genetics contributed to developing and validating the genetic test for the OLFML3 variant.
A variant in OLFML3 is associated with pectinate ligament abnormality and primary closed-angle glaucoma in Border Collies from the United Kingdom. Oliver JAC, Wright H, Massidda PA, Burmeister LM, Mellersh CS.Vet Ophthalmol. 2020 Jan;23(1):25-36. doi: 10.1111/vop.12680. Epub 2019 May 29. [PMID: 31141290]
Arginine to Glutamine Variant in Olfactomedin Like 3 (OLFML3) Is a Candidate for Severe Goniodysgenesis and Glaucoma in the Border Collie Dog Breed. Pugh CA, Farrell LL, Carlisle AJ, Bush SJ, Ewing A, Trejo-Reveles V, Matika O, de Kloet A, Walsh C, Bishop SC, Prendergast JGD, Rainger J, Schoenebeck JJ, Summers KM. G3 (Bethesda). 2019 Mar 7;9(3):943-954. doi: 10.1534/g3.118.200944. [PMID: 30696701]
|G/G||At Risk: Dog has two copies of the OLFML3 mutation and is at a risk for developing Glaucoma. The dog will always pass the mutation to all offspring.|
|G/n||At Risk: Dog carries one copy of the OLFML3 mutation and is at a slight risk of developing Glaucoma. The dog may pass the mutation to offspring.|
|n/n||Clear: Dog is negative for the OLFML3 mutation associated with Border Collie Glaucoma.|