Common Symptoms
Primary open angle Glaucoma (basset fauve de Bretagne type) is an inherited condition of the eye affecting dogs. Affected dogs typically develop increased eye pressure in both eyes between 4-6 years of age. As the pressure in the eye increases, the eyeball increases in size and is painful. Signs of pain in the eye include excessive blinking, tearing and redness. If left untreated, the increased pressure in the eye leads to optic nerve damage and the gradual loss of vision. Dogs with glaucoma are at risk for lens luxation. Symptoms of lens luxation include excessive blinking, squinting and tearing of the eye. Dislocation of the lens can occur in both the forward and backward position within the eye, but dislocation in the forward position is more common and serious. If not treated immediately, lens dislocation will exasperate the glaucoma and vision loss. Other symptoms may include bulging eyes and cataracts.
Testing Tips
Genetic testing of the ADAMTS17 gene will reliably determine whether a dog is a genetic Carrier of primary open angle Glaucoma (basset fauve de Bretagne type). Primary open angle glaucoma (basset fauve de Bretagne type) is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the ADAMTS17 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
References
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Oliver JA, Forman OP, Pettitt L, Mellersh CS. Two Independent Mutations in ADAMTS17 Are Associated with Primary Open Angle Glaucoma in the Basset Hound and Basset Fauve de Bretagne Breeds of Dog. PLoS One. 2015 Oct 16;10(10).
[PubMed: 26474315]
