Cerebellar Degeneration/Cerebellar Abiotrophy

Liaison: Jan Young

Email: jannermd@yahoo.com

Cerebellar abiotrophy is a rare degenerative neurological condition that affects the part of the brain that is responsible for balance and coordination. The cerebellum develops normally and then at some point, usually in a young animal, degeneration begins and symptoms appear. Mental function remains normal. In Samoyeds the degeneration begins very early, before or at birth, and the signs are apparent very early, when they begin to walk. Abiotrophy is progressive and there is no effective treatment. Eventually euthanasia is the best option for the involved Samoyed. Other breeds, with a later onset and milder version of the condition, can have a quality lifespan.

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The degeneration is a result of a progressive dying off of certain neurons in the brain, specifically in the cerebellum, called Purkinje cells. These cells are responsible for communication between areas of the cerebellum that control balance and coordination. Without these cells, the sense of space and distance are lost and balance and coordination become impaired. Although “abiotrophy” means no nutritive factor, it is not actually known what causes the Purkinje cells to degenerate other than as a genetically inherited metabolic disease.

Signs and Symptoms

  • Poor coordination and balance

  • Wide-based stance

  • Stiff or high-stepping gait

  • Clumsy movements, eventually progressing to inability to walk or even stand

  • Tremors of head and sometimes the entire body

Causes

Autosomal recessive gene inheritance.

Autosomal inheritance affects males and females equally in frequency and severity, (unlike X-linked (sex-linked) diseases that affect males more often and more seriously).

Recessive means an animal must have two copies of the defective gene, receiving one copy from each parent. Thus both parents must carry the gene. Carrier parents who have one copy of the gene are normal except for their ability to pass on the gene, and they must be bred with another carrier for the condition to show up. As the gene becomes more common in a breed, the likelihood of both parents being a carrier increases and the frequency of the disease begins to increase.

Risk Factors

Known family member with the condition.

Diagnostic Tests

There are no definitive tests. All routine tests are normal. Diagnosis must rule out other neurological problems or infection. Usually the clinical course of progression is sufficient to make the diagnosis. MRI (magnetic resonance imaging) of the brain might be helpful to differentiate this condition from cerebellar hypoplasia which is similar but is not progressive and has a better prognosis. Microscopic examination of the brain at autopsy can be useful to verify the diagnosis.

Treatment Guidelines

Note: Treatment of animals should only be performed by a licensed veterinarian. Veterinarians should consult the current literature and current pharmacological formularies before initiating any treatment protocol.

There is no treatment. The condition is progressive and eventually a decision is made to euthanize the dog due to poor quality of life.

Management

Parents and siblings of affected dogs should not be bred. Known carriers should not be bred.

References

Cerebellar Disorders in The Merck Veterinary Manual 10th Edition. Ed Kahn, Cynthia M. Pub Merck and Co, Inc. pp 1120-1121 four bones
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Bell JS, DVM. Cerebellar Abiotrophy: Its cause and diagnosis. two bones
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Support Groups

I could not find a support group for canine neurological degeneration.

Congenital and Inherited Disorders of the Nervous System in Dogs in the Merck Manual Pet Health Edition four bones
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Cerebellar Abiotrophy at wikipedia two bones
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Cerebellar Abiotrophy (Ataxia) at the Canine Inherited Disorders Database, University of Prince Edward Island three bones
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Amo AN et al. 2009. Canine cerebellar cortical abiotrophy in two mixed breed littermates. Analecta Veterinaria 29: 39-41. two bones
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Good description of the course of the disease:

Berry ML et al. 2003. Cerebellar abiotrophy in a miniature schnauzer. Can Vet J 44: 657-759. three bones
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