Common Symptoms
Neuronal Ceroid Lipofuscinosis 2 (NCL2) is an early-onset, lysosomal storage disease affecting dogs. NCL2 is due to a deficiency in the Enzyme tripeptidyl peptidase (TPP1), which is necessary to break down certain proteins in the cells. As a result, there is an accumulation of these compounds in cells, which affects the normal function of the brain and nervous system. Affected dogs present with progressive neurologic disease around 9 months of age. Symptoms include loss of learned behavior, mental dullness, Ataxia, loss of vision, weakness, abnormal gait, seizures, tremors and aggressive behavior. Symptoms progress very quickly and dogs typically die by 12 months of age.
Breed-Specific Information for the Standard Longhaired Dachshund
Standard Longhaired Dachshund is included as a breed susceptible to neuronal ceroid lipofuscinosis 2 because of its close relatedness to the Miniature Longhaired Dachshund, which is known to develop this disease due to Mutation of the TPP1 gene. The frequency of the causal mutation in the general Standard Longhaired Dachshund population is unknown.
Testing Tips
Genetic testing of the TPP1 gene in Standard Longhaired Dachshunds will reliably determine whether a dog is a genetic Carrier of neuronal ceroid lipofuscinosis 2. Neuronal Ceroid Lipofuscinosis 2 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 TPP1 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. Standard Longhaired Dachshunds 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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Awano T, Katz ML, O'Brien DP, Sohar I, Lobel P, Coates JR, Khan S, Johnson GC, Giger U, Johnson GS. A frame shift mutation in canine TPP1 (the ortholog of human CLN2) in a juvenile Dachshund with neuronal ceroid lipofuscinosis. Mol Genet Metab. 2006 Nov; 89(3):254-60.
[PubMed: 16621647]
