http://www.theaustralian.com.au/news/world/inherited-alzheimers-detecable-early/story-e6frg6so-1226099156586

Inherited Alzheimer's detectable early 
From: AFP 
July 21, 2011 4:09PM 

A certain type of Alzheimer's can be detected long before loss of memory 
occurs, a study has found. Source: AdelaideNow 

AN inherited form of Alzheimer's disease is likely detectable up to 20 years 
before loss of memory and impaired thinking appear, according to a study. 

Measurable changes in brain chemistry show up years before these signature 
symptoms of the degenerative brain disease set in, researchers reported at the 
Alzheimer's Association International Conference in Paris today.

The findings only apply to a small fraction - less than 1 per cent - of 
Alzheimer's patients afflicted with a rare variant that generally strikes at a 
comparatively young age.

But the ability to identify early chemical warning signs in the brain holds out 
the prospect of preventative treatment not just for these patients, but 
possibly those struck with more common forms of Alzheimer's as well, the 
researchers said.

"We want to prevent damage and loss of brain cells by intervening early in the 
disease process, even before outward symptoms are evident because by then it 
may be too late," said lead research Randall Bateman, a professor at Washington 
University School of Medicine.

The type of Alzheimer's examined in the study arises from a genetic mutation 
that guarantees a person will develop the disease, even if only one parent 
transmits it.
In the vast majority of Alzheimer's cases, however, the disease arises through 
a complex interaction of genetic and environmental factors that remains poorly 
understood.

Worldwide, more than 35 million people are afflicted with the full spectrum of 
the disease's variants, a figure that is expected to triple by mid-century as 
populations age.

For the new study, Bateman and colleagues analysed data from a battery of tests 
given to carriers of the rare mutation.

The same tests - cognitive evaluations, positron emission tomography (PET) and 
magnetic resonance imaging (MRI) scans, searches for telltale markers in 
cerebro-spinal fluid and blood - were also done on siblings who did not carry 
the fateful genetic variant.

Participants destined to develop Alzheimer's not yet exhibiting symptoms were 
mostly in their mid-to-late 30s, while those who did show the first signs of 
the disease were in their mid-40s, the age at which the genetic form usually 
sets in.

Because the disease is so rare, the data had to be gathered by an international 
network of 11 research centres in the United States, Britain and Australia, 
known as the Dominantly Inherited Alzheimer Network, or DIAN.

Researchers presented results in Paris for the first 150 volunteers enrolled in 
the program, which will eventually include 250 more subjects, they said.

The study looked, in particular, for signature changes in brain chemistry 
related to two kinds of proteins, common to all forms of Alzheimer's.

One is a decreased level in spinal fluid of a protein called amyloid-beta42. 
Conversely, this indicates a dangerous build-up of the same protein in some 
areas of the brain that ultimately destroys neurons and leads to irreversible 
brain damage.

The other marker was an increase in tau, the main component of the neuro-fibre 
tangles that also contribute to cell death.

As suspected, the DIAN subjects in their 30s who carried the genetic mutation 
showed both characteristics, whereas their non-carrying siblings did not.

"This suggests that we can measure brain chemistry abnormalities in the 
Alzheimer's gene carriers that begin at least 10 years, maybe even 20 years, 
before the age that their parents saw Alzheimer's symptoms and when they too 
would be expected to see them," Bateman said.

The results had broader implications for the treatment of the disease, noted 
William Thies, Chief Medical and Scientific Officer of the Alzheimer's 
Association.

"We believe we can learn a great deal more about the vast majority of people 
whose Alzheimer's develops as a result of complex interactions among their 
genes, life experiences and other factors," he said.

"Early detection and treatment are crucial if we are to curb the growing 
epidemic."

AFP 

Related Coverage
  a.. Caring for your body can save your mind Herald Sun, 3 hours ago
  b.. Aussie scientists' lead on dementia Adelaide Now, 4 days ago
  c.. Australian scientists unveil Alzheimer's scan The Australian, 7 Jun 2011
  d.. Vaccine for Alzheimer's on way Adelaide Now, 23 Apr 2011
  e.. New drug could halt Alzheimer's Courier Mail, 23 Apr 2011


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