Genetic basis - Goniodysgenesis and early-onset glaucoma in Border Collies are primarily associated with a missense mutation (arginine to glutamine) in the OLFML3 (olfactomedin-like 3) gene. This mutation affects development of the eye's anterior chamber, especially the drainage angle for aqueous humor. The disorder is inherited in an autosomal recessive manner; dogs with two copies of the mutation are at highest risk. Genetic testing can detect carriers and affected dogs.
Pathophysiology - Goniodysgenesis is a developmental abnormality of the iridocorneal angle, leading to narrowing or closure of drainage canals in the eye. Impaired drainage causes buildup of intraocular pressure (glaucoma), which damages the optic nerve and retina, leading to vision loss and blindness. This condition is congenital and often progressive. Severity of drainage abnormalities correlates with risk of developing glaucoma, but not all dogs with goniodysgenesis develop glaucoma.
Complications - Early symptoms include eye pain, sensitivity to light, watery or red eyes, dilated pupils, blinking spasms, and behavioral changes. Progressive optic nerve damage results in visual impairment and eventual blindness. Some dogs live for years with goniodysgenesis but never develop glaucoma, while others rapidly become blind due to high intraocular pressure. Without effective treatment, the damage is irreversible.
Why This Matters to Breeders and Vets - For breeders, preventing affected puppies reduces suffering and improves breed eye health and longevity. Veterinarians use genetic and clinical tools to diagnose, manage, and advise on glaucoma and goniodysgenesis in Border Collies. Understanding the recessive inheritance and variable phenotype assists in counseling breeders and owners. Early detection allows monitoring and management to slow disease progression and support quality of life.