Gene causing incurable brain disorder discovered in canines

The international research team that initiated the present study termed the gene as a first step towards identifying a similar gene to detect the NCL disorder in humans too.

In the past, the researchers have been of the view that NCL is caused by a recessive gene mutation. Anyone having one copy of the gene is called a carrier, who can transmit the disease to their offspring, but having two copies of the mutation can cause the fatal disease.

Dr Natasha Olby, a neurologist at the North Carolina State University and part of the team said, “In dogs, the disease became so prevalent because it was a recessive disease with a 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 added.

More about NCL
One in every 400 American Staffordshire terriers is affected by the disorder that usually occurs in the adult years, due to building up of lipofuscin fatty substances in the brain. The fatty substance destroys the cells in the cerebellum that directly impacts the nervous system.

The disease makes dogs incapable of walking, and eventually leads to the death or forced-euthanizing of the dogs.

Neurodegenerative effects like blindness, loss of motor abilities, and death are some of the effects that occur in humans due to Kufs, the human version of NCL disease. The children version of the disease is called Batten or Jansky-Bielschowsky disease.

Study details
For the present study, the researchers conducted the genetic investigation of the American Staffordshire genome and found the position of the mutation of the Arylsulfatase G gene.

The researchers found that this gene mutation caused a 75 percent drop in the action of the sulfatase enzyme. Low levels of the enzyme were linked to causing NCL, they suggested.

"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 the disease,” stated Dr Natasha Olby.

The researchers are optimistic of analyzing genomes of human beings who have the disease to identify the human variation of the gene. According to them, the identification of the gene can help in developing a possible cure for the disease in both animals and humans.

Findings of the latest study have been detailed in the Aug. 17 edition of the Proceedings of the National Academy of Sciences.