Cerebellar Abiotrophy (CA/ataxia) in the   Australian Kelpie
 by Kathy Gooch
  
The most prevalent genetic disease to affect the  Australian Kelpie  is CA (cerebellar abiotrophy). Because the ramifications of  this condition are  universally widespread it is the most significant genetic  disorder in the  breed. It is also one which is not openly discussed by breeders.  Affected dogs
are usually destroyed, with no necropsy being done and the carrier  parents are  bred to other dogs, only to perpetuate the carrier status. Hopefully  this  article will answer questions regarding this condition and illustrate the  need  for a DNA test and co-operation amongst breeders with regards to submitting   samples.
 What is cerebellar abiotrophy?
The  cerebellum is the  part of the brain that regulates the control and coordination  of movement. In
this condition, cells in the cerebellum mature normally before  birth, but then  deteriorate prematurely causing clinical signs associated with  poor  coordination and lack of balance. The Purkinje cells in the cerebellum are  primarily involved; cells in other areas of the brain may also be 
 affected.
How is cerebellar abiotrophy inherited?
 An autosomal recessive mode of inheritance has been  confirmed or  is strongly suspected for the abiotrophies listed below, with the  exception of  x-linked cerebellar ataxia in the English pointer, which has an  x-linked mode  of inheritance. This means BOTH parents must be carriers or  affected. Carriers  exhibit no symptoms of the disease, while affected dogs can  exhibit a range of
symptoms from mild to severe.
 There seems to be much confusion with regards to how  CA is  inherited in the Australian Kelpie. Click here for more detailed  information.
What breeds are affected by cerebellar  abiotrophy?
  Neonatal  cerebellar  abiotrophy (very rare) - Affected cells start to degenerate  before birth,
so that signs of cerebellar dysfunction are present at birth or  when the pup  first walks.
Beagle, Samoyed 
Postnatal  cerebellar  abiotrophy - Cells in the cerebellum are normal at birth and  begin to
degenerate at variable times thereafter.
Australian Kelpie,  Border  Collie, Labrador Retriever - Clinical signs can be first seen at 6 to 12  weeks,  and the condition can worsen quickly (over a few weeks).  Or clinical signs can be subtle and not appear until the animal is older.
 Cerebellar  and  extrapyramidal nuclear abiotrophy - Cells in other regions of the brain
  deteriorate as well. 
For many breeds and many disorders, the studies to  determine the  mode of inheritance or the frequency in the breed have not been  carried out, or  are inconclusive. We have listed breeds for which there is a  consensus among  those investigating in this field and among veterinary  practitioners, that the  condition is significant in this breed.
 What does cerebellar abiotrophy mean to your dog &  you?
 The cerebellum is the part of the brain that  regulates the control  and coordination of voluntary movement. The clinical signs  of cerebellar  dysfunction in affected dogs may include poor balance, a  wide-based stance  (feet planted far apart), stiff or high-stepping gait,  apparent lack of
awareness of where the feet are (standing or walking with a  foot knuckled  over), and head or body tremors. These signs worsen either quickly  or slowly  (see breed list above). Affected dogs may become unable to climb  stairs or  stand without support. They have normal mental alertness. Clinical  signs can  come in varying degrees of severity from mildly affected egg; slight  head
tremor, slight propping in the rear end to falling over and total loss of   control. Symptoms usually appear at 6 to 12 weeks. Some dogs adapt to the   dysfunction and show little disability.
Where other regions of the brain   are also affected, you may see signs such as behaviour change (loss of house  training, aggression), confusion, blindness, and seizures.
How is  cerebellar abiotrophy diagnosed?
 The clinical signs are suggestive of cerebellar  disease,  particularly if they are seen in a breed in which abiotrophy is known  to occur.  Your veterinarian will do tests to rule out other conditions that can  cause  similar signs. Unfortunately 100% diagnoses can only be determined upon  necropsy of the brains of suspect animals. This re-enforces the need for a DNA  test to determine carrier/affected status.
How is cerebellar  abiotrophy treated?
 There is no treatment for this condition. Dogs do  not recover from  this disorder and usually at some point (depending on the rate  of the  progressive deterioration that occurs), euthanasia becomes the best  option.
Breeding advice
Affected dogs, their parents (carriers of the  trait), and their siblings (suspect carriers) should NOT
be bred. With x-linked cerebellar  ataxia, only male pups are affected, and the  mother is the carrier of the trait.  But this is only in the English Pointer,  not the Kelpie.
CA has become  a widespread problem in  the breed. It is apparent that it is not just an
Australian, American, or  European problem. Because of the relative ease of  importing a dog from Australia,  a Rabies free country, it  is now a global issue. CA is also in both the Working
Kelpie and the Show  Kelpie. More than one Working Kelpie line is affected.  Dr.  Don Robertson, a West Australian geneticist who studied the problem wrote  in an  article on CA in Kelpies for the Australian Veterinary Journal in 1989  “In  the Kelpies studied here, the putative gene appears to have been  inherited from  several dogs which have been prominent in sheep dog trials and
have been widely  used for breeding. Consequently, an increase in the incidence  of cerebellar  abiotrophy in working sheepdog strains can be expected“.  Unfortunately at  present there are very few Working Kelpie pedigrees in which  these lines do not  appear. This once again exemplifies the need for a DNA  test.
 It seems that the reason it does not appear that  CA  is a problem in Australia is the “shoot,  shovel and shut-up attitude” No one talks about affected litters. They  just  disappear in a hole. Then the parents which are obviously carriers are bred  to  other dogs and if nothing shows up the pups are sold as “normal”. The  unsuspecting buyer is than buying a possible carrier. Then the buyer purchases  another dog from the same lines in the hopes of doing a line breeding. Then as  bad luck would have it that dog is a carrier. These dogs are bred and BANG!!!!!  You have a litter of affected pups. The ones showing symptoms are shot and the  non affected ones sold and bred. Odds are they are carriers as well so the  problem continues and continues and continues. Some of these carriers have been  exported out of the country only spreading the problem. The issue with CA as  is that it can appear at six weeks or at two or three years . This is a terrible loss to many people of a beloved pet, not to   mention the time and money put into training a  dog.
 If a DNA test was developed, affected  individuals  could be euthanized and carriers could be desexed and still used as  working  dogs. Also the non carriers of a litter could be bred and the positive
traits of  those lines still passed on with out the worry of genetic problems.  If breeders  think that they would lose money as a result of this DNA test, exactly the  opposite would occur. If a pup was sold with a CA clear certificate  the value of  that pup would be greater than those without. Also because of the  cost of  export, breeders and buyers would be put in a position to have testing
done  before dogs left the country.  Because the Kelpie has a relatively small gene  pool  to eliminate excellent carriers from the gene pool would be madness. The  KEY is  to KNOW THE STATUS of the dogs you are breeding.