A WOMAN who has evaded Alzheimer’s disease despite half her relatives getting it could hold the clues to how to prevent it, a study suggests.
The memory-robbing condition plagued her family in Colombia for generations — with some developing it in their 40s.
GettyMRI image of brain showing area of Alzheimer patient.[/caption]
Despite this, the woman has stayed fit and healthy in her late 70s and US researchers now believe they know why.
They found she had two copies of a gene called APOE, known as the Christchurch mutation, which they think could help prevent Alzheimer’s from progressing.
Dr David Holtzman, of Washington University in St Louis, said: “Any protective factor is very interesting, because it gives us new clues to how the disease works.
“As people get older, many begin to develop some amyloid accumulation in their brains. Initially, they remain cognitively normal.
“However, after many years the amyloid deposition begins to lead to the accumulation of the tau protein. When this happens, cognitive impairment soon ensues.
“If we can find a way to mimic the effects of the APOE Christchurch mutation, we may be able to stop people who already are on the path to Alzheimer’s dementia from continuing down that path.”
Around 944,000 Brits are currently living with dementia and experts predict the numbers will exceed one million by the end of the decade.
Alzheimer’s disease is the most common form of the condition, and is thought to be caused by build-ups of proteins in the brain, including tau and amyloid.
There is currently no cure for the disease, although three promising drugs to slow down its progress are currently in trials.
The study, published in Cell, looked at families who have a mutation in a gene called presenilin-1, which causes a larger buildup of amyloid in people’s 20s.
This normally causes cognitive decline as early as middle age, but the researchers identified an exception in the woman.
She had more amyloid in her brain in her 70s than her relatives did in their 40s but did not show the saim signs of brain injury and cognitive impairment.
Dr Holtzman said: “One of the biggest unanswered questions in the Alzheimer’s field is why amyloid accumulation leads to tau pathology.
“This woman was very, very unusual in that she had amyloid pathology but not much tau pathology and only very mild cognitive symptoms that came on late.
“This suggested to us that she might hold clues to this link between amyloid and tau.”
Researchers looked at mice with high amounts of amyloid and genetically modified them to carry the same Christchurch mutation she had.
After injecting tau into their brains, the team found the mice did not see the same spread of the protein that normally occurs in brains with high amounts of amyloid.
This meant they were less likely to suffer brain degeneration and cognitive problems.
Dr Holtzman said: “If we can mimic the effect that the mutation is having, we may be able to render amyloid accumulation harmless, or at least much less harmful, and protect people from developing cognitive impairments.”