Dog gene linked to human brain disease

Scientists who discovered a gene mutation that causes a fatal neuro-degenerative disease in American Staffordshire (Pit Bull) terriers say the same gene may also be linked to a similar, rare fatal brain disease in humans.

The discovery of the gene associated with a variant of neuronal ceroid lipofuscinoses (NCLs), a family of diseases that lead to mental and motor deterioration and death,  may lead to improved screening and diagnosis of the disease in dogs.

It may also be an early first step in developing a cure for NCLs in both dogs and humans, according to the multinational team of researchers.
 

In American Staffordshire terriers, also known as American Pit Bull Terriers, the disease causes mental and motor deterioration leading to death. Adult-onset NCL affects one of every 400 registered American Staffordshire terriers, according to research team member Dr Natasha Olby, an associate professor of neurology at North Carolina State University.

Carriers may never have symptoms

"The disease became so prevalent because it was a recessive disease with late onset. Carriers of a single copy of the mutated gene never develop symptoms, and dogs with two copies of the gene might not show symptoms until five or six years of age, so the mutation was able to take hold in the breeding population," she explained. 

Genetic analysis revealed the location of the specific gene and an entirely new mutation that has not been reported in people. 

In humans, NCLs such as Batten disease mostly affect children, but there is an adult-onset form called Kufs' disease that causes gradual death of brain neurons, resulting in vision loss, epilepsy, loss of co-ordination and dementia, according to the National Institute of Neurological Disorders and Stroke. 

The unique nature of the mutation in dogs means that researchers can now conduct tests to determine if the same mutation is responsible for Kufs' disease in humans, according to Olby. 

"The canine disease is a good model of the adult human form of the disease. We hope that this discovery will provide insight into the development of this disease," she said. 

The study was published in the Proceedings of the National Academy of Sciences. (August 2010)

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