Neuronal ceroid lipofuscinsosis 1 (NCL1) is a rare lysosomal storage disease identified in a Miniature Dachshund. NCL1 is due to a deficiency in the Enzyme palmitoyl protein thioesterase (PPT1), 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. The affected dog presented with progressive neurologic disease at 9 months of age though the owner stated that the symptoms began a “number of months” earlier. Symptoms included a lack of muscle coordination, abnormal gait, and difficulty balancing and jumping. The dog also displayed signs of Dementia including aimless wandering behavior with episodes of confusion, depression, aggressive behavior, loss of learned behavior, blindness, seizures and frequent barking. These symptoms rapidly became more severe and the dog was euthanized at 14 months of age.
Genetic testing of the PPT1 gene will reliably determine whether a dog is a genetic Carrier of neuronal ceroid lipofuscinosis 1. Neuronal ceroid lipofuscinosis 1 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 PPT1 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.
Sanders DN, Farias FH, Johnson GS, Chiang V, Cook JR, O'Brien DP, Hofmann SL, Lu JY, Katz ML. A mutation in canine PPT1 causes early onset neuronal ceroid lipofuscinosis in a Dachshund. Mol Genet Metab. 2010 Aug; 100(4):349-56.