Border Collie Goniodysgenesis (GD) is a developmental anomaly of the iridocorneal angle that predisposes to primary glaucoma. It is one of the most important causes of blindness in the Border Collie.

Goniodysgenesis refers to abnormal development of the eye's drainage angle, where the aqueous humor drains from the anterior chamber. When the angle is malformed, drainage is compromised, causing a progressive increase in intraocular pressure (IOP) that damages the optic nerve and retina.

The resulting glaucoma can be acute (episodes of intense pain with ocular redness) or chronic (progressive and silent deterioration of vision). Without treatment, it leads to irreversible blindness.

- Border Collie: in the Pugh 2019 series, 11 of 16 cases were homozygous for c.590G>A and 3 were wild-type homozygotes; of 90 controls, 71 wild-type, 17 heterozygous and 2 homozygous for the variant: strong but incomplete association.
- The variant is documented in Border Collie (and Siberian Husky in OMIA:001223); other breeds with goniodysgenesis have different forms.
- Goniodysgenesis is detected gonioscopically in dogs from 6 months of age.

- Goniodysgenesis: malformed iridocorneal angle (visible gonioscopically)
- Episodes of acute glaucoma: ocular redness, pain (tearing, closed eyelids), opaque cornea, mydriatic pupils
- Chronic glaucoma: progressive vision loss, gradual increase in IOP, remodeling of the eyeball (buphthalmia)
- Progressive iridal atrophy
- Pigment dispersion in the cornea
- Corneal neovascularization in advanced cases
- Can be unilateral or bilateral (frequently bilateral in the long term)

Goniodysgenesis in the Border Collie was described in the 1990s as an important cause of glaucoma in the breed. Later studies identified a locus on chromosome 5 associated with the disease, but the specific causative mutation has not yet been fully identified.

The breed has a recognized genetic predisposition, and several lineages have been documented with a higher incidence. The current genetic test (available in laboratories such as Animal Genetics) detects associated variants but is not 100% predictive.

- Gonioscopy by a certified ophthalmologist in all breeding animals (screening for pectinate ligament dysplasia).
- Genotype OLFML3 if a test is available; avoid matings between homozygotes.
- Measure intraocular pressure periodically in dogs with goniodysgenesis (risk of acute angle closure).
- Do not mate dogs with confirmed goniodysgenesis; inform about the incomplete penetrance.
- Educate about acute glaucoma as an emergency (it can cause blindness in 24-72 hours).

Border Collie goniodysgenesis is characterized by pectinate ligament dysplasia and risk of primary angle-closure glaucoma. Diagnosis is gonioscopic; intraocular pressure may be normal initially. Differential diagnosis with other causes of canine glaucoma. Ophthalmological management includes control of intraocular pressure and, when indicated, medical treatment (prostaglandin analogues, beta-blockers, carbonic anhydrase inhibitors) or surgery.

1. Pugh CA et al. 2019, variante Arg197Gln en OLFML3 como candidata de goniodisgenesia grave y glaucoma en el Border Collie (PMID 30696701)
2. Oliver JAC et al. 2020, una variante en OLFML3 asociada a displasia del ligamento pectinado y glaucoma primario de ángulo cerrado en Border Collie del Reino Unido (PMID 31141290)
3. Oliver JAC et al. 2017, displasia del ligamento pectinado en Border Collie, Vizsla húngaro y Golden retriever (PMID 27999154)
4. OMIA:001223 Glaucoma primario de ángulo cerrado (OLFML3)