The international study, called DIAN (Dominantly Inherited Alzheimer’s Network), has so far recruited 150 people. They come from families affected by the rare genetic changes that cause Alzheimer’s. This form of Alzheimer’s accounts for about 1% of Alzheimer’s cases worldwide. They represent an ideal study group to find out about the sequence and rate of Alzheimer’s brain changes that happen before any detectable symptoms in memory or thinking occur. Those who have the genetic mutation and are destined to develop Alzheimer’s can be compared to siblings without the mutation.
Results indicate that proteins (amyloid and tau) in cerebro-spinal fluid (CSF) are altered in people with the genetic mutation. The changes were seen at least ten years before the expected age of the onset of dementia symptoms. The protein levels were not affected in family members without the genetic mutation. These findings are consistent with what is being seen in the common, late onset form of Alzheimer’s which is caused by a complex interaction of genes, lifestyle and other factors.
Findings from imaging studies show that amyloid builds up in the brain long before clinical symptoms appear. It appears the build up is in different parts of the brain to those affected by common Alzheimer’s.
The findings, together with detailed cognitive test results, give the most comprehensive data of pre-clinical and symptomatic early onset Alzheimer’s disease to date. The DIAN Therapeutic Trials Unit plans to start prevention trials in this population.
Their findings have been reported at the American Alzheimer’s Association International Conference in Paris today.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, said:
“By studying people at the highest risk of developing Alzheimer’s symptoms because of their genes we can also learn about the vast majority of people who develop Alzheimer’s because of complex factors.
“We need to be able to intervene early in Alzheimer’s disease to brain cells from damage before it is too late. Uncovering Alzheimer’s changes in the brain before any symptoms show means it’s possible these may be targeted for future prevention trials in people with genetic Alzheimer’s. It’s likely such trials will pave the way for prevention trials for all forms of Alzheimer’s.
“Numbers of people living with Alzheimer’s are over half a million in the UK alone; research is the only answer to defeating this disease. Investment across all areas of research – diagnosis, prevention and treatment – is urgently needed.”
Alzheimer’s Research UK