Experts 'find earliest early onset Alzheimer's signs'

Some of the earliest symptoms of early onset inherited Alzheimer's disease have been uncovered by experts more than 20 years before signs of the illness usually appear.

Researchers discovered there were differences in the brains of an extended family from Columbia predisposed to develop early onset inherited Alzheimer's in an early form.

The disease begins long before people notice the effects, with studies showing it affects the brain 10 to 15 years before signs appear.

Only after the death of enough brain cells do the signs of dementia start appearing, with some areas of the brain losing up to 20% of their brain cells before the disease becomes apparent.

The Columbian patients who have familial Alzheimer's were studied by a team from Arizona's Banner Alzheimer's Institute.

Because of a genetic mutation, members of the family nearly always get the disease during their 40s, with Alzheimer's usually appearing after they reach 75.

A group of 20 people with the mutation, aged between 18 and 26, had brain scans as part of the research, which was published in the Lancet Neurology.

It was found that the brain scans of these people were already different from scans of 24 people who did not have the mutation.

Members of the family also had higher levels of beta-amyloid protein in the fluid, which bathes the spinal cord and brain.

Finding the signs of early onset Alzheimer's before it happens

According to researchers, differences could be found 'more than two decades before' Alzheimer's would appear in high-risk patients.

One of the scientists involved, Dr Eric Reiman, said: 'These findings suggest that brain changes begin many years before the clinical onset of Alzheimer's disease.

'They raise new questions about the earliest brain changes involved in the predisposition to Alzheimer's and the extent to which they could be targeted by future prevention therapies.'

Dr Simon Ridley, the head of research at Alzheimer's Research UK, said: 'Although early-onset inherited Alzheimer's is rare and may not entirely represent the more common late-onset form, the findings highlight changes can take place in the brain decades before symptoms show.

'Mapping what changes happen early in the brain will help scientists to improve detection of the disease and allow potential new treatments to be tested at the right time.'

Copyright Press Association 2012