Health Conditions
Information regarding Genitic Health Issues in Cocker Spaniels.
PRA (Progressive Retinal Atrophy)
An inherited eye disease found in many breeds of dogs with varying ages of onset. There are various types of PRA but the one most commonly seen in Cockers is GPRA (General Progressive Retinal Atrophy) also known as prcd-PRA. This results in night blindness gradually leading to total blindness.
In Cockers, PRA has a variable age of onset, from as early as 18 months to as late as 7 years. It is inherited as a simple Autosomal Recessivegene, meaning that a copy of the PRA gene must be inherited from both parents for the disease to occur. With recessive conditions like PRA, there are 3 genetic categories, affected, normal and carriers. Affected animals have two copies of the faulty PRA gene, one inherited from each parent. Carrier animals have one faulty copy of the PRA gene but appear perfectly healthy and cannot be distinguished from normal dogs by eye screening. Normal animals are entirely free of the faulty gene.
The difficulty was that until recent years breeders had no way of identifying which category their breeding stock fell into as the only screening test available in the UK (eye testing by a BVA Panellist) could only determine if a dog was clinically clear of the disease at the time of testing. It could not determine whether the dog was a carrier or whether the dog would go on to develop the disease at some time in the future. For some time, a marker gene test for prcd-PRA had been available from the American company, Optigen which gave a good indication of the status of dogs tested. Optigen then identified the mutation gene which causes prcd-PRA in English Cockers and this test is now available to breeders in the UK & Europe as well as in the US, enabling breeders to identify whether their dogs are genetically clear, carriers or affected with the disease.
Dogs which have been prcd-PRA DNA tested as either Carriers or Affecteds should only be mated to dogs which have been DNA tested as Clear/Normal to avoid producing affected progeny.
Familial Nephropathy (FN)
Familial Nephropathy (FN), a fatal kidney disease in young Cockers, was unfortunately quite prevalent in the breed in the 1980's until research instigated by The Cocker Spaniel Club (UK) established that this was a hereditary condition with a simple recessive mode of inheritance (as with PRA).
A Control Scheme was set up by The Cocker Club (UK) in the mid 1980's under which, all dogs & bitches known to have produced confirmed cases of FN were withdrawn from breeding and details of these carrier animals were published & made available to members & other breeders so that sensible decisions could be made in the selection of breeding stock. The success of this Control Scheme can be demonstrated by the fact that in recent years, only a small number of confirmed cases have been reported.
Research was carried out in the US to develop a gene test which identifies carriers of this disease.
Dogs which have been DNA tested as Carriers of this disease should only be mated to dogs which have been tested as Clear/Normal to avoid producing affected puppies.
In Australia our breeders are very lucky to be able to benefit from the genetic tests via several companies worldwide including www.orivet.com.au
Adult Onset Neuropathy (AON)
A progressive weakness due to a neuropathy has been recognized as an autosomal recessive, hereditary disorder in English Cocker Spaniels by the research team at the University of Missouri Animal Molecular Genetic Lab.
Clinical signs typically begin between 7.5 and 9 years of age and consist first of an uncoordinated gait or wobbling in the hind limbs. The stance in the hind limbs is wide-base and the hocks will drop lower to the ground. The weakness eventually progresses to also involve the front limbs. When dogs become non-ambulatory in all limbs, difficulty in swallowing also becomes apparent.
The neurologic signs seem to progress gradually over 3 to 4 years and more slowly than those of degenerative myelopathy.
All English Cocker Spaniels clinically affected with this form of neuropathy have tested clear for the mutation that underlies DM. So far the disease has only been clinically diagnosed in English Cocker Spaniels. However, the mutation has been detected in Field Spaniels, although it is very rare.
Further information about the test is available here
https://www.ofa.org/diseases/dna-tested-diseases/adult-onset-neuropathy
Contact Details
Shellie GalpinDelaneys Creek, QLD, Australia
Phone : 0404887457
Email : [email protected]