New insights into dementia and genetic risk

An international research team comprising several Australian scientists has identified a series of genes believed to be associated with an increased risk of hereditary Alzheimer's disease, in research that represents the largest study to date focused on genetics and dementia.

The researchers believe their findings, which were recently published in the journal Nature Genetics, could improve our understanding of how dementia progresses, while supporting the development of new drugs for its treatment and prevention.

The project included a study of the genomes of more than 111,000 people living with Alzheimer's disease, alongside a control group comprising 670,000 people without the disease.

The team identified the presence of 42 new 'risk regions' within the genomes of those participants living with Alzheimer's disease, which occurred much less frequently amongst the control group. Further observations of these risk regions identified 31 genes that can be linked to the genetic processes associated with dementia.

Associate Professor Michelle Lupton of Australia's QIMR Berghofer Medical Research Institute, who was part of the research team, said this work is the largest research study that has ever been conducted on the genetic basis of Alzheimer’s disease, and includes data from hundreds of thousands of research participants from all over the world.

"75 regions of the genome were identified through this work, 42 of which are novel and have never been linked to the disease before," said Lupton.

Based on these findings the team was able to refine the 'genetic risk score' currently used to estimate the likelihood of a person developing dementia following a diagnosis of mild cognitive impairment. The results of the study also provide insights into the pathophysiological processes of dementia and could help identify new biological features and therapeutic targets.

"This research will help identify new drug targets for Alzheimer’s disease, and potentially help to identify those with a high risk of developing the disease to access preventative treatment," said Lupton.

Professor Elizabeth Coulson, Professor of Neuroscience at The University of Queensland and co-Chair of the Dementia Australia Research Foundation Scientific Panel, described the findings as a large and comprehensive report of genetic risk, conducted at an overwhelming scale, even for those in the field.

"Perhaps most promisingly, the researchers noted many of the genes identified through this study encode molecules involved in processes already predicted or previously shown to play a role in the development of Alzheimer's disease. These include the processing of the

Amyloid precursor protein and its trafficking around the cell, control of the brain’s immune system function, and immunological signalling responses," said Coulson.

"Therefore, while there is still a lot of work to be done to understand how these genetic variations result in a genetic nudge down the dementia path, these findings will allow scientists to focus their attention on these key processes, as they look to develop new candidate drugs to treat people living with dementia or at a higher risk."

Are you interested in supporting local dementia research? The Dementia Australia Research Foundation supports innovative Australian research and is funded by donations from the public, and by private and philanthropic organisations. If you’d like to know more about or to support the foundation, please visit the research foundation page.