Neuronal Ceroid Lipofuscinosis 10 (NCL10) is a lysosomal storage disease affecting American Bulldogs. NCL10 is due to a deficiency in the activity of the Enzyme cathepsin D, 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 typically present between 1 to 3 years of age with progressive neurologic disease. Symptoms include a lack of muscle coordination, abnormal gait and difficulty balancing. Disease progression is slow, but dogs are generally euthanized within 2 years of diagnosis when they can no longer stand or walk on their own.
Breed-Specific Information for the American Bulldog
The Mutation of the CTSD gene associated with neuronal ceroid lipofuscinosis 10 has been identified in the American Bulldog. Though the exact frequency in the overall American Bulldog population is unknown, 36.6% out of 123 American Bulldogs were carriers of the mutation and 9.8% had two copies of the mutation and were at-risk/affected.
Genetic testing of the CTSD gene in American Bulldogs will reliably determine whether a dog is a genetic Carrier of neuronal ceroid lipofuscinosis 10. Neuronal Ceroid Lipofuscinosis 10 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 CTSD gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may 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. American Bulldogs 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.
Awano T, Katz ML, O'Brien DP, Taylor JF, Evans J, Khan S, Sohar I, Lobel P, Johnson GS. A mutation in the cathepsin D gene (CTSD) in American Bulldogs with neuronal ceroid lipofuscinosis. Mol Genet Metab. 2006 Apr; 87(4):341-8.
Evans J, Katz ML, Levesque D, Shelton GD, de Lahunta A, O'Brien D. A variant form of neuronal ceroid lipofuscinosis in American bulldogs. J Vet Intern Med. 2005 Jan-Feb; 19(1):44-51.