What causes cerebellar ataxia?

Cerebellar ataxia is cause by problem in the part of the brain called the cerebellum. Any disease that damages the cerebellum can produce the signs of ataxia. The first step in helping any dog with ataxia is to perform diagnostic tests to rule out other causes besides hereditary disease, such as brain tumors, infections, or congenital malformations. This is a critical step since some of these other conditions may be readily treatable. An MRI scan of the brain can show the shrinkage of the cerebellum that occurs with hereditary ataxia.


Shrinkage of the cerebellum (arrows) may be visible on MRI scans in dogs with hereditary cerebellar ataxia. .

Normal dog

Dog with cerebellar ataxia

The Purkinje cells which normally line up between the layers of the cerebellum (arrows) are lost in hereditary ataxia.

In hereditary ataxias, a genetic defect leads to degeneration of the cerebellum. There are many variations on this disease. In some, only a limited portion of the cerebellum degenerates and the dogs can still walk. In the most common type of hereditary ataxia, only one cell type in the cerebellum, the Purkinje cells, degenerate. In other breeds, additional portions of the movement systems in the brain degenerate. In dogs with these more extensive degenerations, the signs will be more severe. The more severely affected dogs are incapacitated by their disease, while more mildly affected dogs can live with their disabilities.

 


Offspring of two carrier parents have a 25% chance of being affected. In this pedigree, males are shown as squares & females as circles; shaded symbols are affected dogs.
How is it inherited? Most of the hereditary ataxias in dogs appear to be autosomal recessive traits. In recessive traits, a dog can carry the gene responsible, but not be affected. If two carriers of the gene are bred, however, affected pups can result. Identifying carriers can be difficult, especially when the disease does not show up until later in life.

What breeds are affected? Many different breeds have been affected with this condition. As with any genetic disease, it can be difficult for even the most conscientious breeder to completely eliminate the condition from the breed until a DNA test is developed. Several breed clubs, with the help of the Canine Health Foundation of the American Kennel Club, have funded research to develop such DNA tests.

How can I help? If you own a dog that you suspect has hereditary ataxia, please contact us. You will still need to see your veterinarian and if necessary consult with a veterinary neurologist to be sure of the diagnosis. If they confirm that this could be hereditary ataxia, you can help with search for the genes responsible for the disease so that future dog lovers will not have to face the prospect of seeing their companion afflicted with these diseases.


Many different breeds of dog have been affected with hereditary ataxia. Research being supported by the AKC Canine Health Foundation hopes to find DNA tests that will eliminate the condition.