Neuronal Ceroid Lipofuscinosis (Tibetan Terrier Type)

Other Names: Adult Onset Neuronal Ceroid Lipofuscinosis, Amaurotic idiocy, Batten disease, NCL
Affected Genes: ATP13A2
Inheritance: Autosomal Recessive
Mutation: chr2:81210367 (canFam3): 1 bp deletion (del G)
Breed(s): Tibetan Terrier

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Common Symptoms

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited lysosomal storage disorders. 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, leading to a range of nervous system disorders. Dogs affected with NCL (Tibetan terrier type) present with progressive loss of vision and behavior changes beginning around 4 to 7 years of age. Symptoms include a lack of muscle coordination, abnormal gait and difficulty in balancing and jumping. Affected dogs may also display aimless wandering behavior with episodes of confusion, depression, aggression, seizures and frequent barking. These symptoms become more frequent and severe over time. As the disease progresses, dogs may lose sensory skills and vision. Signs of Dementia may include loss of learned behavior, irritability and aggression. There is currently no treatment for the disease.

Testing Tips

Genetic testing of the ATP13A2 gene will reliably determine whether a dog is a genetic Carrier of NCL (Tibetan terrier type). NCL 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 inheriting one copy and being a carrier of the ATP13A2 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do 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. 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

  • Farias FH, Zeng R, Johnson GS, Wininger FA, Taylor JF, Schnabel RD, McKay SD, Sanders DN, Lohi H, Seppälä EH, Wade CM, Lindblad-Toh K, O'Brien DP, Katz ML. A truncating mutation in ATP13A2 is responsible for adult-onset neuronal ceroid lipofuscinosis in Tibetan terriers. Neurobiol Dis. 2011 Jun; 42(3):468-74. [PubMed: 21362476]
  • Kluth, S, Eckardt J, Distl O. Selection response to DNA testing for canine ceroid lipofuscinosis in Tibetan terriers. Vet J. 2014 Sep;201(3):433-4. doi: 10.1016/j.tvjl.2014.05.029. [PubMed: 24929534]
  • Wöhlke A, Philipp U, Bock P, Beineke A, Lichtner P, Meitinger T, Distl O. A one base pair deletion in the canine ATP13A2 gene causes exon skipping and late-onset neuronal ceroid lipofuscinosis in the Tibetan terrier. PLoS Genet. 2011 Oct; 7(10):e1002304. [PubMed: 22022275]