NCL is a defect in metabolism leads to a build up of a pigmented toxin called ceroid lipofuscin within cells, including those of the brain and retina.

The disease is progressive in nature and show declines in the functioning of both cognitive and motor skills.

Example of issues that occur include seizures, cognitive impairment, anxiety, increased sensitivity to sound and vision loss.

Unfortunately this disease usually greatly shorten the lifespan of the dogs diagnosed with it, with most diagnosed dogs being eithanized at around 23 months of age.