What is Retinopathy?
Retinopathy is an eye disease that causes the photoreceptor cells in the dog’s retina to degrade over time. More recently retinopathy has been found in the Vallhund breed in the uk, although cases were found in other countries before this time none were confirmed here until 2013. The disease can vary in its severity and onset with some dogs being found affected at around 2-4 years old and other dogs having clear eye tests before being found affected in old age. Retinopathy is not painful and in mild cases the dog may be night blind where it cannot see properly in the dark. In the most severe cases a dog may become blind.
What causes Retinopathy?
Retinopathy is a hereditary condition. A marker associated with retinopathy was identified by Finnish researchers and a marker test was developed at Genoscoper. While it is unknown if multiple genetic mutations cause retinopathy one mutation that does has been identified by the Animal Health Trust. This mutations mode of inheritance is autosomal recessive and makes the dog very likely to develop retinopathy at some point in its life time, although at what age this would happen it if does is impossible to tell. So for a dog to be affected by this mutation it must inherit a copy of the gene from both parents.
What are breeders doing about Retinopathy?
Originally breeders had to solely rely on pedigree research and eye testing to try to avoid breeding two dogs very likely to produce affected puppies. However now with the introduction of the two new tests breeders have the option to use this to further help lower the risk of puppies developing retinopathy. Below is information on all tests.
Animal Health Trust Retinopathy DNA Test: This mutations mode of inheritance is autosomal recessive, so for a dog to be affected by this mutation it must inherit two copies of the gene, one from both parents. With a simple swab from the inside of a dogs cheek the AHT can check the dogs DNA for this mutation and report the results back to the owner as either ;
Clear: The dog does not have this mutation and will not develop retinopathy from the tested mutation as the dog does not have it.
Carrier: The dog has one copy of the mutation and as such it will also not develop retinopathy from this tested mutation as it does not have 2 copies. However it can pass this mutation on to its offspring if bred.
Genetically Affected: The dog has two copies of the mutation and as such will be very likely to develop retinopathy at some point in its life time, although when cannot be known. If bred this dog will always pass on one copy of the mutation to its offspring.
Using this test a breeder can make choices when picking who to breed by knowing the possible breeding outcomes.
Clear X Clear = Each puppy born has a 100% chance to be clear, 0% chance to be a carrier or genetically affected.
Clear X Carrier = Each puppy born has a 50/50 chance to be clear or a carrier, 0% chance to be genetically affected.
Clear X Genetically Affected = Each puppy born has a 100% chance to be a carrier, 0% chance of being clear or genetically affected.
Carrier X Carrier = Each puppy born has a 50% chance to be a carrier, 25% chance to be clear and 25% chance of being genetically affected.
Carrier X Genetically Affected = Each puppy born has a 50/50 chance of being born either a carrier or genetically affected.
Genetically Affected X Genetically Affected = Each puppy has a 100% chance to be genetically affected, 0% chance to be clear or a carrier.
For more information on this test or to order a kit please click here to visit the AHT website
BVA/KC/ISDS Eye Exam: This is an eye exam with certain vets who are on the panel of examiners for the scheme. This exam screens the dogs for eye diseases and will issues a certificate either showing the dog is clear or will list what eye disease the dog has. The exam looks for any eye condition rather than just one specific one. The advice from the scheme is that dogs used for breeding should be re-examined annually .
For more information on this test click here to visit the BVA Website.
Finnish Marker Test: While not causing retinopathy the marker tested for is associated with it. The test only give a potential risk level for a dog to develop retinopathy, it does not say the dog will or will not develop it. The dogs results are either Clear (AA), Carrier (AG), or At Risk (GG).
Clear (AA): Dog has two normal copies of the marker. In the Finnish studies only 4.7% of affected dogs fell into this category, so the dog is classed as a minor risk factor.
Carrier (AG): Dog has one copy of the normal marker and one copy of the mutated one. In the study 25% of affected dogs were in this category, so the dog is more at risk than a clear but still a minor risk factor compared to GG dogs.
At Risk (GG): Dog has two copies of the mutated marker. 69.8% of affected dogs were in this category. These dogs have an 18-fold risk factor of developing retinopathy at some point.
For more information on this test or to order a kit please click here to visit the MyDogDNA website.
How is Retinopathy Diagnosed and Treated?
Retinopathy can only be diagnosed by examining the retina at the back of the eye. This will be done by a specialist vet either a BVA or EVCO Eye Specialist. This exam will be the same as the eye testing described above.
There sadly is no cure for retinopathy, as this condition is not painful there is no pain management required. Depending on the severity an owner may need to take no special care with their vallhund in the milder cases. In the more server cases depending on the vision loss owners may need to take extra care when walking their dog and not moving the furniture around may help dogs who have lost their vision or has poor vision.
What can puppy buyers do?
When looking to add a Swedish Vallhund puppy to your home, you should only get a puppy from a litter where the parents have a current clear eye certificate and is also tested with the AHT DNA Test. Your breeder should be happy to show you the result certificates of both mum and dad. You can also check the eye exam has been done online, using the health test checker on the Kennel Club website.