Researchers uncover dementia gene

Affects up to 100,000 Canadians. Discovery will allow scientists to seek cure for disease that kills within 10 years

NICHOLAS READ, CanWest News Service; CP contributed to this report

Published: Monday, July 17, 2006

Two University of B.C. researchers have helped discover a genetic mutation that can cause the second-most-common form of dementia in people 65 and under.

Dr. Ian Mackenzie of the Department of Pathology and Laboratory Medicine, and Dr. Howard Feldman, director of the UBC Hospital Clinic for Alzheimer’s Disease and Related Disorders, helped identify the gene that can cause frontotemporal dementia along with researchers from the Mayo Clinic in Florida.

FTD, which occurs mainly in people in their 50s and early 60s, results in severe personality changes, language problems and death within five to 10 years of its onset.

The condition represents about 15 per cent of all dementia cases worldwide, including up to an estimated 100,000 in Canada.

The research was published Sunday in the online edition of Nature magazine.

Working with their Florida colleagues, Feldman and Mackenzie identified the gene responsible for the production of a protein called progranulin, which aids cell growth and function.

People affected with the genetic form of FTD fail to produce sufficient levels of this protein, and this is believed to lead to the disease.

The genetic disorder is thought to cause FTD in 25 to 50 per cent of all people suffering from it. It is distinct from Alzheimer’s disease in that people affected with it retain their memory.

Doctors don’t yet understand the cause of FTD in other sufferers.

However, when genetics are responsible for FTD, up to half of all family members that carry the mutated gene can be affected by it.

“It’s a dementia that occurs in middle life, meaning the most typical patients we see are in their 50s and 60s,” Feldman said in a phone interview.

“They’re still often in employment and looking after youngish families. So it’s a very devastating illness.”

While there is still no cure, the discovery means a search for one can begin.

“There’s an under-expression of a growth factor that helps nerve cells function and survive,” Feldman said.

“So the idea would be to find a way now to enhance the body’s ability to produce the protein or to see if we can supplement its production somehow. This may some day take the curse of the illness away.”

The current discovery also means members of families in which the disease is known to occur can undergo genetic testing to see if they are affected by it.

The disease also occurs sporadically in people, though researchers don’t know how or why.

But Mackenzie said it should now be possible to test for progranulin levels in these patients as well.

FTD sufferer Lynn Jackson, 51, of Richmond, B.C., called the discovery “a great thing.”

“Now that they have the cause, then they’ll be able to find the cure more easily,” Jackson said.

She was diagnosed in 1999, and now experiences problems with her speech and movement. She also had to quit her job and go on long-term medical disability insurance.

Despite her enthusiasm for the UBC discovery, she is not counting on a cure being found in time to save her.

“I don’t know if I’m that hopeful for myself because it will take time to get a cure,” Jackson said.

FTD is often misdiagnosed as Alzheimer’s disease, depression, psychosis or even alcoholism.

Mackenzie said people suffering from FTD can become either withdrawn or display inappropriate emotional outbursts, such as laughing or crying at the wrong time.

They also may develop inappropriate social behaviour such as swearing, masturbating in public or shoplifting.

“They lose their self-awareness so they don’t realize they’re doing anything wrong,” Mackenzie said.

Vancouver Sun

© The Gazette (Montreal) 2006

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