Thousands 'misdiagnosed' with Alzheimer's as finding could pave way for new dementia research
Hundreds of thousands of older people diagnosed with Alzheimer's are probably suffering from a different disease, which is why drugs trials keep failing, scientists said.
In new findings hailed as the "most important research to be published on dementia in the past five years", experts said that around one-third of people over 85 are probably suffering from Late disease, even though they show signs of Alzheimer's.
Alzheimer's is caused by build-ups of sticky plaques of amyloid and tau proteins in the brain, damaging brain cells, leading to memory loss and confusion. For years, scientists noticed that a large number of elderly people who died with symptoms of Alzheimer's had no amyloid or tau in their brains.
Instead, they appeared to have a build-up of a different protein known as TDP-43.
The finding is important, because most drugs trials for Alzheimer's have focused on clearing out the amyloid, and all so far have failed, leading to big pharmaceutical companies abandoning research.
Dr Pete Nelson, of the University of Kentucky, who led the research, said: "Late disease probably responds to different treatments than Alzheimer's, which might help explain why so many past Alzheimer's drugs have failed in clinical trials."
Like Alzheimer's disease, Late disease affects the memory and thinking capacity. However, it develops more slowly than Alzheimer's.
Researchers found roughly 25pc of over-85s have enough misfolded TDP-43 to affect their memory or thinking abilities, and more may have the disease without symptoms.