Common Symptoms
Neuronal ceroid lipofuscinosis 8 (Australian shepherd type) is a lysosomal storage disease affecting dogs. Affected dogs lack a specific Enzyme necessary for normal metabolism. As a result, there is an abnormal accumulation of waste compounds primarily in the cells of the nervous system. Affected dogs typically present around 8 to 12 months of age with changes in behavior including increased sensitivity to sounds and a loss of learned behaviors such as housetraining and responsiveness to commands. With time, affected dogs will display various signs of progressive neurological disease including mental dullness, weakness, compulsive movements, anxiety, aggression, loss of balance, blindness, seizures and death. Death or euthanasia usually occurs by 2 years of age.
Testing Tips
Genetic testing of the CLN8 gene will reliably determine whether a dog is a genetic Carrier of neuronal ceroid lipofuscinosis 8 (Australian shepherd type). Neuronal ceroid lipofuscinosis 8 (Australian shepherd type) 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 CLN8 gene mutation. Reliable genetic testing is important for determining breeding practices. 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. Dogs 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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Guo J, Johnson GS, Brown HA, Provencher ML, da Costa RC, Mhlanga-Mutangadura T, Taylor JF, Schnabel RD, O'Brien DP, Katz ML. A CLN8 nonsense mutation in the whole genome sequence of a mixed breed dog with neuronal ceroid lipofuscinosis and Australian Shepherd ancestry. Mol Genet Metab. 2014 Aug;112(4):302-9
[PubMed: 24953404]
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O'Brien DP, Katz ML. Neuronal ceroid lipofuscinosis in 3 Australian shepherd littermates. J Vet Intern Med. 2008 Mar-Apr;22(2):472-5
[PubMed: 18371036]