Dogs with RVED develop retinal degeneration from around four years of age which, if untreated, leads to blindness.
In partnership with James Oliver, Head of Ophthalmology at DWR Veterinary Specialists (pictured), researchers set out to discover why some Cocker Spaniels have such low vitamin E levels in their blood, despite it being present at normal amounts in their diet
James helped to design the study, recruit cases and collect samples.
Cathryn Mellersh, Senior Research Associate at the Canine Genetics Centre, said: “The team strongly suspected a genetic cause and has been trying to discover the responsible gene for several years with the help of owners and vets, who have contributed DNA samples.
“Thanks to updated information on the canine genome, Katherine Stanbury, one of our research associates, found a mutation in the alpha tocopherol transfer protein gene which is causative of the disease.
“This gene is responsible for getting vitamin E into the blood stream.
"We now know that RVED is a recessive disease, meaning that affected dogs must have two copies of the faulty gene to develop low vitamin E levels and retinal degeneration.”
The team’s DNA test can be used by dog breeders to find out if dogs carry the gene mutation, so they can avoid matings which result in affected puppies being born.
Cathryn said: “This DNA test is a rare example of one which not only can be used to identify dogs that are carrying the mutation and thus reduce the frequency of the mutation in future generations, but also has the incredible benefit of providing a sight-saving treatment option for dogs with the disease.
“From the research we have done we estimate that there could be several hundred Cocker Spaniels alive today that have two copies of this mutation, whose eyesight could be saved by this test.”
A DNA test for the mutation that causes RVED is now available from Canine Genetics Testing, which operates alongside researchers from the Canine Genetics Centre.
www.cagt.co.uk.
The team’s RVED research can be viewed at https://academic.oup.com/g3journal/advance-article/doi/10.1093/g3journal/jkaf016/7985679?searchresult=1