Neuronal ceroid lipofuscinosis 5 (NCL5) is a lysosomal storage disease affecting Border Collies. Affected dogs lack adequate activity of a specific Enzyme necessary for normal cellular 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. Affected dogs typically present between 15 and 20 months of age with behavioral changes. Symptoms initially include non-responsiveness to commands, loss of interest in play or other dogs, irrational fears, hallucinations, disorientation and aggression. Symptoms become more frequent and severe over time and may include Ataxia, falling, seizures, aimless wandering, abnormal gait, lethargy and vision loss. Dogs with this disease rarely live beyond 32 months of age.
Genetic testing of the CLN5 gene will reliably determine whether a dog is a genetic Carrier of neuronal ceroid lipofuscinosis 5. Neuronal ceroid lipofuscinosis 5 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 CLN5 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.
Melville SA, Wilson CL, Chiang CS, Studdert VP, Lingaas F, Wilton AN. A mutation in canine CLN5 causes neuronal ceroid lipofuscinosis in Border collie dogs. Genomics. 2005 Sep; 86(3):287-94.
Mizukami K, Chang HS, Yabuki A, Kawamichi T, Kawahara N, Hayashi D, Hossain MA, Rahman MM, Uddin MM, Yamato O. Novel rapid genotyping assays for neuronal ceroid lipofuscinosis in Border Collie dogs and high frequency of the mutant allele in Japan. J Vet Diagn Invest. 2011 Nov; 23(6):1131-9.
Mizukami K, Kawamichi T, Koie H, Tamura S, Matsunaga S, Imamoto S, Saito M, Hasegawa D, Matsuki N, Tamahara S, Sato S, Yabuki A, Chang HS, Yamato O. Neuronal ceroid lipofuscinosis in Border Collie dogs in Japan: clinical and molecular epidemiological study (2000-2011). ScientificWorldJournal. 2012;2012:383174. Epub 2012 Jul 31.