Scientists isolate gene that protects against Alzheimer's

London, July 13 (IANS) DNA screening of nearly 2,000 people has helped identify a mutated gene which could help protect against Alzheimers, potentially paving the way to a new therapy.

Mimicking this variant with a drug could stop Alzheimer's in its tracks, say neurologists. The gene is known as APP (amyloid precursor protein) and makes a chemical called amyloid-beta which clumps together in the brain forming plaques and blocks neurons (nerve cells) from signalling one another.

Kari Stefansson, chief executive of Icelandic company deCODE Genetics in Reykjavik, and colleagues said the rare mutation results in a 40 percent reduction in the formation of these harmful 'plaques,' the journal Nature reports.

Researchers also found dementia-free elderly people with the variant have better cognitive function between the age of 80 and 100 than those with the normal version, according to the Daily Mail.

Mutations in the APP gene have already been implicated in early-onset Alzheimer's that runs in families, but had not been linked to the common form of the disease that occurs in later life.

Stefansson said the research supports previous ideas that interfering with the gene, which can be achieved with existing drugs, may prevent dementia. Despite almost 40 years of research, scientists have made little progress in developing drugs that inhibit interactions between proteins.

This is, in part, because the drug molecules are many times smaller than the proteins, so even if they can attach themselves to the larger molecules they are too small to prevent other proteins binding elsewhere.

The degenerative condition is the most common form of dementia and affects more than 300,000 people in Britain alone and affects one in 14 people over the age of 65. It can be inherited in some cases.