Goniodysgenesis and Glaucoma Susceptibility - Border Collie
Goniodysgenesis is a condition cause by the abnormal and incomplete development of the anterior chamber which can result in excessive pressure buildup in the eye. If the condition remains untreated, increased pressure in the eye will eventually result in permanent damage to the optic nerve and blindness.
Most forms of glaucoma can be placed into two categories, primary and secondary. The term primary glaucoma is used to describe those types of glaucoma caused by an inherited physical or physiological trait that an animal has been predisposed to based on genetics. These traits are generally recessive and passed down from one generation to the next.
Secondary glaucoma is a term referred to when the disease is triggered by something other than genetics. Trauma in the eye can cause bleeding, swelling, and inflammation to occur. As the eye heals, scar tissue may form, impacting the normal drainage of fluid resulting in increased pressure in the eye.
More than 40 dog breeds are genetically predisposed to goniodysgenesis including the Flatcoated Retriever, Welsh Springer Spaniel, Cocker Spaniel, American Cocker Spaniel, English Springer Spaniel, Basset Hound, Border Collie, Golden Retriever, Leonberger and Dandie Dinmont Terrier. Unfortunately, a large percentage of dogs affected by 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, eye appears to have fallen into the socket, raised third eyebrow, dog winces when you touch his or her head, watery eyes, behavioral change (hiding, refusal to eat), red eye, and dilated pupils.
The discovery of a genetic variant on the OLFML3 gene was performed at The Roslin Institute, 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. Based on this discovery, Animal Genetics develop an assay to detect the genetic variant associated with Border Collie Glaucoma. A paper will be published outlining all of the work.
Animal Genetics accepts buccal swab, blood, and dewclaw samples for testing. Sample collection kits are available and can be ordered at Canine Test Now.
Test Is Relevant to the Following Breeds:
Animal Genetics offers DNA testing for Glaucoma susceptibility in Border Collies. The genetic test verifies the presence of the recessive mutation and presents results as one of the following:
|G/G||Affected||The dog carries two copies of the mutant gene and is homozygous for the OLFML3 mutation associated with BCG. The dog is very susceptible to developing glaucoma and will always pass a copy of the mutation to its offspring.|
|N/G||Carrier||One copy of the OLFML3 mutation associated with BCG. Dog is a carrier and can pass on a copy of the defective gene to its offspring 50% 0f the time.|
|N/N||Clear||Sample tested negative for the OLFML3 mutation associated with BCG, and will not pass on the defective gene to its offspring.|