Alzheimer’s breakthrough?

Discovery of a defective gene may help scientists develop tests to identify people at greatest risk of Alzheimer’s disease and tailor-made drug therapies to help them.

“It’s another clue to the way in which this disease comes about, another piece of the puzzle,” Dr. Peter St. George-Hyslop, director of the centre for research in neurodegenerative diseases at the University of Toronto and co-leader of the study, told the National Post.

“Every time you get a piece of the puzzle and you can relate it to something else in the puzzle, you’re that much closer to knowing what the picture on the puzzle is,” he added.

The gene, called SORL1, normally directs proteins away from the “forbidden” zones of the brain. It is here that molecular toxin can build up and eventually destroy brain cells in people with Alzheimer’s. Researchers believe that defective copies of the gene are found inside many people who will eventually develop the debilitating neurodegenerative disease.

Currently, about 435,000 Canadians have Alzheimer’s and other related dementias. The disease, which has no cure, is expected to impact more people as the population ages. According to the Toronto Rehabilitation Institute, an estimated 750,000 Canadians will have Alzheimer’s disease or a related dementia by 2031.

The study, published in the journal Nature Genetics, provides important insight on the biochemical processes that can devastate memory, personality and cerebral function in people with Alzheimer’s.

Researchers analyzed DNA from several hundred Canadians for the study, as well as the DNA from 6,000 volunteers from various ethnic groups including Caribbean Hispanics, Northern European, African Americans and Israeli Arabs. The study was a collaboration between researchers at the University of Toronto, Boston University and Columbia University.

Researchers hope the discovery of SORL1 will eventually lead to a genetic test to help them identify people with greater risk as Alzheimer’s as well as therapies tailored to fit a person’s gene profiles.

“Ultimately we want to be at a stage where people don’t have a `fear’ of being tested because they’ll know once they are tested there (will be) various therapeutic strategies to lower the risk,” said study co-author Dr. Lindsay Farrer, chief of genetics at Boston University.

However, researchers say that much work is yet to be done, including replicating the findings and confirming that “SORL1 is indeed a bona fide Alzheimer’s disease causing gene,” said St. George-Hyslop.

About Alzheimer’s disease*
• Over 360,000 Canadians (1 in 20) over 65 have Alzheimer’s and related dementias.

• The biggest risk factor for Alzheimer’s is a family history of the disease. Most of the people affected by this disease are over the age of 65.

• It is estimated that 750,000 Canadians will have Alzheimer’s disease or a related dementia by 2031.

• The impact of Alzheimer’s and related dementias on individuals, families, caregivers, health care professionals and the health care system is enormous.

• Canada currently spends an estimated $5.5 billion to care for people with Alzheimer’s/dementia.
* Toronto Rehabilitation Institute