Cerebellar abiotrophy(ataxia)

What is ... ?: 

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 are the cells in the cerebellum which are primarily involved; cells in other areas of the brain may also be affected.

How is ... inherited?: 

Inheritance is autosomal recessive. The defective gene has been identified and causes a defect in glutamate metabolism. (For more information, see cerebellar abiotrophy Online Mendelian Inheritance in Animals (OMIA). Faculty of Veterinary Science, University of Sydney. 2011.

What does ... mean to your dog & you?: 

Because the cerebellum regulates the control and coordination of voluntary movement, the clinical signs of cerebellar dysfunction 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. Signs may appear at birth or later (as listed below) and worsen either quickly or slowly. Affected dogs may become unable to climb stairs or stand without support. They have normal mental alertness.
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.
Neonatal cerebellar abiotrophy (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
Early onset(birth to ~6 weeks): Airedale terrier, beagle, collie (rough), coton de tulear, Finnish harrier, Jack Russell terrier, Irish setter, miniature poodle, Rhodesian ridgeback, and samoyed.
Onset at 6 weeks to 6 month: Australian kelpie, Bernese mountain dog, border collie, bull mastiff, coton de tulear, Gordon setter, Kerry blue terrier, and Labrador retriever.
Later onset: Brittany spaniel, Gordon setter, old English sheepdog. Clinical signs progress slowly (months to years).

How is ... diagnosed?: 

Typically, pups are normal at birth and then begin to develop signs consistent with cerebellar disease (as listed above) at varying ages, depending upon the breed. The diagnosis is based on the clinical signs, breed, and age of onset. Your veterinarian will also do tests to rule out other conditions that can cause similar signs. It is important to differentiate this disorder from cerebellar hypoplasia, which is a non-progressive disorder (ie., does not worsen over time).

How is ... treated?: 

There is no treatment for this condition. Dogs do not recover from this disorder and usually at some point (which varies with the rate of progressive deterioration), euthanasia becomes the best option.

For the veterinarian: 

Routine diagnostic tests are normal with this condition and a definitive diagnosis can only be made by brain biopsy or on post-mortem. However, generally with this condition, the cerebellum appears grossly normal. Histopathologic abnormalities are often minimal and do not seem to correlate with the severity of cerebellar signs.

Breeding advice: 

 Affected dogs, their parents (carriers of the trait), and their siblings (50% chance of being a carrier) should not be bred.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.
 

Resources: 

Bailey KS. Cerebellar Abiotrophy. In: Côté E, ed. Clinical Veterinary Advisor Dogs and Cats. Missouri: Mosby Elsevier, 2007:186-187.
Coates JR. Weeble, Wobble, Roly, Poly: A Study of Cerebellar Disease. Proc. ACVIM Forum, 1996:684-687. This reference provides a comprehensive breed list, with associated clinical and pathologic findings.
Sargan DR. IDID - Inherited diseases in dogs:web-based information for canine inherited disease genetics. Mamm Genome. 2004 Jun;15(6):503-506.


What breeds are affected by ... ?
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