Florey News

Florey scientists quantify biggest genetic risk factor for Alzheimer’s disease

Scientists from the Florey Institute of Neuroscience and Mental Health in Melbourne and Stanford University in California have identified a genetic variant, carried by 20 per cent of the population, that confers a five-fold higher risk of early memory problems due to dementia.

Published in the most recent issue of the prestigious journal Neurology, the findings confirm that a variation of the ApoE gene, known as ApoE4, is the biggest risk factor besides age for developing Alzheimer’s and other dementias.

The Florey’s Dr Yen Ying Lim, who led the study, says, “Around 1 in 5 people carry at least one copy of ApoE4 in their genome. Those who have one copy are more likely to start declining in mental performance up to 13 years before those who don’t carry the variation.”

The results came from studying 595 people without dementia in America who volunteered to take part in the Alzheimer’s and Dementia Neuroimaging Study, which has been running for the past decade.

The participants were either healthy or had mild mental impairment. Their brains were scanned every two years to determine whether they had any amyloid build up – the toxic protein thought to be responsible for Alzheimer’s disease.

The researchers followed those people for five years and showed that in people who started out as amyloid negative, ApoE4 increased the rate of accumulation of amyloid. This means those people are more likely to become amyloid positive in future years.

Dr Lim says, “Much like cardiovascular disease, where we try to identify people at higher risk - whether that’s due to lifestyle or family history - and then start them on preventative statins to reduce their cholesterol, we want to identify people with higher risk factors of developing Alzheimer’s so that we can intervene early with new and emerging treatments.”

“This is the holy grail of Alzheimer’s research – to develop a primary preventative treatment to stop the Alzheimer’s disease process before it even starts.”

“These results from the American study are fascinating, but they need to be replicated, and made statistically more robust. To that end, we are now recruiting for an Australian-based study, called the Healthy Brain Project, which will be Australia’s largest ever online cognitive study. We aim to recruit 5000 healthy Australians aged between 40 and 65 and measure their mental performance over three years. We will also determine their genetic status for a number of genes, including ApoE, known to increase people’s Alzheimer’s risk.”

The study is based at the Florey's Melbourne Dementia Research Centre

To join the study as a volunteer, please visit brainproject.org.au, or email healthybrainproject@florey.edu.au

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