Common Symptoms
Cerebellar degeneration is an inherited, progressive neurological disease affecting old English sheepdogs. Affected dogs present between 6 months and 4 years of age with slowly progressive neurological dysfunction due to death of nerve cells in a part of the brain known as the Cerebellum, which plays an important role in coordinated movement. Clinical signs include tremors, high-stepping gait, and uncoordinated movements (Ataxia) which become progressively more severe over a course of months to years. Though the speed of progression is variable, affected dogs are often euthanized due to quality of life concerns.
Breed-Specific Information for the Old English Sheepdog
The Mutation of the RAB24 gene associated with cerebellar degeneration has been identified in old English sheepdogs. Though the exact frequency in the overall old English sheepdog population is unknown, approximately 11% out of 254 old English sheepdogs tested were carriers of the mutation.
Testing Tips
Genetic testing of the RAB24 gene in old English sheepdogs will reliably determine whether a dog is a genetic Carrier of cerebellar degeneration. Cerebellar degeneration is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the RAB24 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Old English sheepdogs that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
References
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Agler C, Nielsen DM, Urkasemsin G, Singleton A, Tonomura N, Sigurdsson S, Tang R, Linder K, Arepalli S, Hernandez D, Lindblad-Toh K, van de Leemput J, Motsinger-Reif A, O’Brien DP, Bell J, Harris T, Steinberg S, Olby NJ. Canine Hereditary Ataxia in Old English Sheepdogs and Gordon Setters Is Associated with a Defect in the Autophagy Gene Encoding RAB24. PLoS Genet. 2014 Feb; 10(2): e1003991.
[PubMed: 24516392]
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De Lahunta A, Fenner WR, Indrieri RJ, Mellick PW, Gardner S, Bell JS. Hereditary Cerebellar Cortical Abiotrophy in the Gordon Setter. J Am Vet Med Assoc. 1980 Sep 15;177(6):538-41.
[PubMed: 7440348]
