The charity fighting disease and injury in animals

Hereditary Cataract in the Australian ShepherD

* NEW STUDY *

We are currently conducting a new study to investigate the possibility that more than one form of HC exists in Australian Shepherds. If your dog has been clinically diagnosed with cataracts by a veterinary ophthalmologist or your dog is clear of cataracts and is eight years of age or over with a current clear eye examination certificate, we will test your dog free of charge upon receipt of a copy of the dog’s eye examination. Please email sally.ricketts@aht.org.uk for further details.

Cataracts are a leading form of blindness in the dog. During 2006 our researchers identified a genetic mutation in a small number of Australian Shepherds affected with Hereditary Cataract (HC). To further investigate the relationship between the mutation and HC in the breed, we recruited and analysed DNA samples from a large number of additional Australian Shepherd from the UK, Europe and USA.

The results show conclusively that the mutation is a risk factor for the development of cataract in the Australian Shepherd. Our study indicates that the likelihood of developing bilateral posterior cataracts is approximately 12 times higher for Australian Shepherds that carry the mutation (either one or two copies) than it is for dogs that don’t carry the mutation.  The mutation is dominant, which means that dogs only need to inherit a single copy of the mutation to be at increased risk of developing cataracts. This also means that dogs/bitches that have produced offspring with cataracts are not necessarily carriers of the mutation as the affected offspring may have inherited a single copy of the mutation from their other parent.

Using the information gained from this research, we have developed a DNA test for the mutation. This test will detect those dogs that carry either one or two copies of the HC mutation, and those that are clear of the mutation.

Breeders will be sent results identifying their dog as belonging to one of three categories:

This dog is CLEAR of the hereditary cataract mutation. This dog does not carry any copies of the HC mutation and will neither develop the form of HC that is associated with this mutation, nor pass a copy of the HC mutation to any of its offspring.

This dog has ONE COPY of the hereditary cataract mutation and is at increased risk of developing cataracts during its lifetime. The dog will pass the mutation to 50% (on average) of its offspring.

This dog has TWO COPIES of the hereditary cataract mutation and is at increased risk of developing cataracts during its lifetime. The dog will pass the mutation to all of its offspring.

If a dog with one copy of the mutation is bred with another dog with one copy of the mutation approximately 75% of the puppies will inherited at least one copy of the mutation and be at increased risk of developing cataracts.

If a dog with two copies of the mutation is bred with either a clear dog or a dog with one copy of the mutation all the puppies will inherit at least one copy of the mutation and be at increased risk of developing cataracts.

We are currently investigating the possibility more than one genetic form of HC exists in Australian Shepherds. If your dog has been clinically diagnosed with cataracts by a veterinary ophthalmologist we will test you dog free of charge upon receipt of a copy of the dog’s eye examination. Please email DNAtesting@aht.org.uk for further details.

Tests can be ordered through our Webshop.