Page URL:

Gene discovery sheds light on cause and prevention of Alzheimer's

16 March 2009
Appeared in BioNews 499

A gene mutation linked to the accumulation of the peptide beta-amyloid in the brain - thought to cause Alzheimer's - has been shown to trigger the disease when individuals carry two copies and help protect against the disease when they carry only one, according to a study published in the journal Science last week. This is the first time that a recessive mutation - meaning that two copies of the gene variant are required to cause the illness - has been linked to Alzheimer's.

The researchers discovered the gene variant by examining the DNA of a family in which a 44 year old man carrying two copies of the gene, known as A673V, developed severe Alzheimer's, while his 88 year old aunt and several other relatives, carrying only one copy of the gene, remained healthy. Scientists have previously linked a small proportion of Alzheimer's cases to three other mutations in a gene called APP, which produces amyloid precursor protein; however these only required only one copy of the gene to cause the disease. Fabrizio Tagliavini and colleagues at the Carlo Besta National Neurological Institute in Milan, Italy, found that mixing the mutant and normal versions of the amyloid precursor protein together in a test tube resulted in far less beta-amyloid formation than either the mutant or normal versions of the protein alone, explaining why individuals with one copy of each seem less likely to develop Alzheimer's disease.

'What makes it interesting is that you can have this apparently relatively innocuous change and end up with some individuals having full expression of the disease, and in others, protection,' commented Steve Snyder, an Alzheimer's researcher at the National Institute on Aging, in Bethesda, Maryland, US, who was not involved in the study. 'It calls upon the entire Alzheimer's disease genetics community to take a fresh look at the number of genes involved,' he told Bloomberg Press.

If scientists can develop a means of delivering a copy of the normal version of the protein into the cells of patients with two copies of the defective gene, it could help to prevent the onset of Alzheimer's, however extensive research will be needed before a therapy can be developed for humans, stress the researchers.

11 April 2011 - by Alison Cranage 
International scientists including researchers at Cardiff University, UK and the University of Pennsylvania, USA have discovered five genetic variations associated with Alzheimer's disease. The findings are published in two papers in the journal Nature Genetics...
10 January 2011 - by Dr Lux Fatimathas 
UK researchers have identified the genetic mutation that caused an 18th Century Irish man to grow to a height of seven and a half feet. This was the result of a growth disorder called gigantism. Studies of four modern day Irish families also presenting with similar growth disorders, showed they too expressed the same genetic mutation....
7 September 2009 - by Ailsa Stevens 
British and French researchers this week announced the discovery of three new genes linked to late-onset Alzheimer's disease, certain variations in which may increase a person's risk of developing the disease by 10-15 per cent. If new drugs could be developed to counter the effects of these mutations, it could help to prevent 20 per cent, the equivalent of 100,000 cases, of Alzheimer's disease in the UK per year, the researchers claim....
19 July 2009 - by Adam Fletcher 
Findings published last week suggest that people are not troubled upon learning they are at higher risk of developing Alzheimer’s disease. Writing in the New England Journal of Medicine, researchers at the Boston University School of Medicine, US, led by Dr Robert Green, measured participants’ anxiety levels following results of a genetic test. The paper arrives amidst debate on how harmful direct-to-customer genetics testing - offered by companies such as 23andMe and DeCodeMe - might actuall...
19 January 2009 - by Dr Will Fletcher 
A team from the Mayo Clinic College of Medicine in Jacksonville, Florida, US, has discovered a new gene variant that seems to increase the risk of developing Alzheimer's disease. The discovery is the first evidence of gender-specific risk factor for the disease because the variant is on...
3 November 2008 - by Ailsa Stevens 
A study examining the genomes of more than 1,300 families has revealed four new genes potentially linked to the most common late-onset form of Alzheimer's disease, according to a study published in the American Journal of Human Genetics last week. The researchers, based at the Massachusetts General...
7 July 2008 - by Alison Cranage 
New research, published last month in the journal Cell, has identified a previously unknown gene, named CALHM1, that is linked with Alzheimer's disease. A certain allele, or version, of this gene, was found to be associated with an increased risk of developing late-onset Alzheimer's. A large international...
Log in to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.