The woman immune to Alzheimer’s

Scientists hope pensioner holds genetic key to curing the condition

PAUL THOMAS IS AWAY

AN ELDERLY woman who is genetically immune to Alzheimer’s disease could provide the key to unlocking a major breakthrough in treatment.

Scientists discovered the woman, who is in her 70s, in Colombia during a dementia screening study.

They found her brain was so packed with the amyloid plaques that are partly responsible for Alzheimer’s that she would have been expected to show severe symptoms in her 40s.

But at three decades older she was still perfectly lucid, with no signs of cognitive decline or dementia.

British experts said last night the discovery could ‘change the thinking’ of the entire field of dementia research and could ‘take us a step closer towards a cure’.

Alzheimer’s disease – the most common form of dementia – affects 500,000 people in Britain and tens of millions more around the world. As yet there is no drug on the market that slows the course of the disease, let alone prevents it entirely.

The woman at the centre of the study was discovered by a team of experts led by Harvard Medical School, who found she had a rare genetic mutation they believe protected her against Alzheimer’s.

Without this mutation to the APOE3 gene she would have been expected to show a significant deterioration in her brain cells three decades earlier.

But scans showed her brain had changed remarkably little for someone of her age.

Experts believe her mutation stops the development of ‘tau’ – a toxic protein that causes tangles in the brain.

Usually people with Alzheimer’s have both amyloid plaques tau tangles, but this woman had no tangles despite a high volume of plaques.

The researchers tested 117 of her relatives, many of whom also had high levels of amyloid plaques and had started showing signs of dementia in their 40s due to a separate genetic mutation that increased their Alzheimer’s risk.

Like them, the woman at the centre of the study carried this high-risk mutation, but she was the only one with the APOE3mutation that seemed to protect her against it. Researcher

Dr Yakeel Quiroz, of Harvard’s Massachusetts General Hospital, whose findings were published last night in the journal Nature Medicine, said: ‘This single case opens a new door for treatments of Alzheimer’s disease... promoting resistance even in the face of significant brain pathology.’

Fellow researcher Dr Eric Reiman, of the Banner Alzheimer’s Institute, said: ‘This study underscores the... profound impact even one research volunteer can have in the fight against this terrible disease. We hope our findand ings galvanize and inform the discovery of APOE-related drug and gene therapies.’

Fiona Carragher, chief research officer at the Alzheimer’s Society, said it was a turning point, adding: ‘This is a rare example where the study of just one person could change the thinking of a whole research field.

‘The hope is that this exciting scientific advance could lead to new treatments and take us a step closer towards a cure.’

But Professor John Hardy, a neuroscientist at University College London and one of the world’s top dementia experts, warned against expecting too much from the study, adding: ‘It is a single-case report and it is prudent to be cautious.’