SECOND GENE FOR EARLY ONSET ALZHEIMER'S DISEASE DISCOVERED BY CANADIAN SCIENTIST

Toronto - August 31, 1995: The international team of scientists led by Dr. Peter St George-Hyslop, who two months ago discovered the gene for early onset Alzheimer's disease, has found a second gene which is reponsible for the disease. Dr. St George-Hyslop is a member of the Canadian Genetic Diseases Network and Director of the University of Toronto's Centre for Research in Neurodegenerative Diseases.

Canadian Genetic Diseases scientist, Dr. Johanna Rommens of University of Toronto and Toronto's Hospital for Sick Children, collaborated with Dr. St George-Hyslop in both discoveries and is a member of the research team.

The findings of the team will be published in the August 31 issue of the journal Nature. Recent announcements of similar results from other research groups were derived from the Network team's original discoveries.

The new gene, which is located on chromosome one, is associated with a less severe form of early onset familial Alzheimer's disease than the gene which Dr. St George-Hyslop discovered in June of this year. "The fact that both genes cause Alzheimer's disease and both produce similar proteins suggests that they have similar and possibly sequential functions in a complex biochemical pathway which eventually leads to Alzheimer's disease", said Dr. St George-Hyslop.

"The genes are similar enough that knowledge developed from studying one gene will be relevant to the second gene", said Dr. Rommens. Dr. St George-Hyslop added "This is the first time we have found a causative agent and have immediately known how it relates to one of the other known causes. By combining separate pieces of knowledge, like these two pieces, we will eventually develop a clear picture of the complex biochemical processes involved in this disease."

Dr. St George-Hyslop commented that "Once we understand the biochemical processes of early onset Alzheimer's disease we will have a basis from which to design rational treatments".

He believes that since some people with the disease do not have mutations on the gene he has just discovered, or any of the three other known early onset Alzheimer's disease genes, there is at least one more early onset Alzheimer's disease gene yet to be discovered.

Dr. Michael Hayden, Scientific Director of the Canadian Genetic Diseases Network, said "We congratulate Dr. St George-Hyslop and his team on the rapid progress of their discoveries. The collaborations made possible through the Network were crucial in these important developments in Alzheimer's research."

The Canadian Genetic Diseases Network is a consortium of 38 of Canada's leading geneticists who are linked with twelve universities across Canada, 10 core technology facilities, and 8 industrial partners to form an "institute without walls".

Under a mandate from the federal government's Networks of Centres of Excellence Program, the Network is working closely with the University of Toronto, Hospital for Sick Children, and commercial partners to continue the leading-edge research efforts in Alzheimer's disease.

CANADIAN SCIENTIST LEADS DISCOVERY OF GENE FOR EARLY ONSET ALZHEIMER'S DISEASE

Toronto - June 29, 1995: An international team of scientists led by a member of the Canadian Genetic Diseases Network, Dr. Peter St George-Hyslop of the University of Toronto, has discovered the gene responsible for early-onset Alzheimer's disease, the most severe form of the disease.

A member of the team, Dr. Johanna Rommens, also of the Canadian Genetic Diseases Network and of Toronto's Hospital for Sick Children, collaborated closely with Dr. St George-Hyslop and was instrumental in the discovery.

The findings of the team will be published in the June 29 issue of the journal Nature.

Early onset Alzheimer's disease is a rare but extremely aggressive form of Alzheimer's disease that affects individuals aged 30 to 60 years. It progresses faster than the more common late onset forms of the disease which typically affects people after age 65, but it is otherwise identical.

"Alzheimer's disease is a very complex disorder", said Dr. St George-Hyslop. "Some types of the disease have purely genetic roots - early onset being one of them. We know that there are at least three and probably four or five different genes that are involved in the inherited susceptibility to this disease." He added that in most forms of the disease, there is probably a mixture of genetic predisposition and environmental cause.

Three years ago, Dr. St George Hyslop's team found evidence that the gene responsible for Alzheimer's disease was to be found on chromosome 14. After examining various genes in this region without finding the mutations responsible for the disease, the team began a new search. In collaboration with Dr. Johanna Rommens, they employed a specialized cloning technique to isolate genes from chromosome 14 and, after looking at 19 additional genes, they eventually found one bearing the mutations which are specific to people with early onset Alzheimer's disease.

Commenting on the next step in research on the disease Dr. Rommens said, "This gene will provide insight into the cause and progression of Alzheimer's disease. The mutations already provide important clues to how the defective protein product malfunctions."

Speaking from his laboratory at the University of British Columbia, Dr. Michael Hayden, Scientific Director of the Canadian Genetic Diseases Network, expressed his delight that the Network has played a role in supporting Dr. St George-Hyslop's research. He commented "The Network's continuing commitment together with the support of Network core technology facilities and collaborations across Canada will be crucial to the rapid progress of Dr. St George-Hyslop's work towards improved diagnostics and ultimately new therapies for this disease".

The Canadian Genetic Diseases Network is a consortium of 38 of Canada's leading geneticists who are linked with twelve universities across Canada, 10 core technology facilities, and 8 industrial partners to form an "institute without walls". The network carries a mandate under the federal government's Networks of Centres of Excellence Program to perform leading-edge research and to work with industry partners on detection and treatment of genetically-transmitted disease.