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Another 42 genes linked to Alzheimer’s have been found by scientists, in what they claim is a major discovery from the biggest study of its kind.
Alzheimer’s is the most common form of dementia, and slowly robs people of their memories and independence. No cure exists yet, although drugs can help alleviate some of the symptoms.
But experts say the new findings could could open the door to new ways of treating the disease.
An international team of scientists discovered 75 regions of DNA linked to the cruel disease. These included 42 genetic quirks never before linked to Alzheimer’s.
They have also developed a genetic risk score to evaluate which at risk patients are most likely to go on to develop the disease within three years.
Experts welcomed the new study as providing another “piece of the puzzle” of what causes the disease but added it will take more work to turn this into new treatments for patients.
A plethora of research has indicated that an individual’s genes can increase the risk of developing Alzheimer’s, with the disease known to run in families.
Dr Rebecca Sims, co-author from Cardiff University, claimed the findings more than “double the number of identified genes” thought to influence the risk of Alzheimer’s.
She said, “It provides exciting new targets for therapeutic intervention and advances our ability to develop algorithms to predict who will develop Alzheimer’s in later life.”
Cardiff’s Professor Julie Williams another author of the study added, “This is a landmark study in the field of Alzheimer’s research and is the culmination of 30 years’ work.
“The results support our growing knowledge that Alzheimer’s disease is an extremely complex condition, with multiple triggers, biological pathways and cell types involved in its development.”
She added that while lifestyle factors like smoking, exercise and diet influence our risk of developing Alzheimer’s, our genes were the single most important factor.
“60-80 per cent of disease risk is based on our genetics and therefore we must continue to seek out the biological causes and develop much-needed treatments for the millions of people affected worldwide,” she said.
The UK experts carried out the research alongside colleagues from the French National Institute of Health and Medical Research.
They analysed genomes, the total genetic instructions that make a person who they are, of just over 111,000 people with Alzheimer’s disease and 677,000 healthy controls.
Some of these genes were found to play a role in the two proteins which build-up in the brains of people with Alzheimer’s: amyloid-beta and tau.
Other genes were found to be related to a dysfunction of the body’s immune system and mircogila — an immune cell in the nervous system that normally clears away the build-up of toxic materials in the brain.
Researchers also found genes governing the activation of a protein called tumor necrosis factor alpha, which is involved in triggering inflammation in the body, is also linked to Alzheimer’s disease.
The researchers published their genetic findings — dubbed a “major discovery” — in the journal Nature Genetics.
Lead author Dr Jean-Charles Lambert claimed their work would help scientists learn more about the biological mechanisms at play in Alzheimer’s.
Dr Lambert revealed how they used the findings to create a genetic risk score, which could predict which patients will be struck down with Alzheimer’s.
While not yet ready for use as a clinical tool, the neuroscientist claimed it could help spot patients who may see the most benefit from drug trials.
Dr Susan Kohlhaas, director of research at Alzheimer’s Research UK, welcomed the new study.
“Creating an extensive list of Alzheimer’s disease risk genes is like having the edge pieces of a puzzle put together,” she said.
“And while this work doesn’t give us the full picture, it provides a valuable framework for future developments.
“The research also, however, tells us just how complex Alzheimer’s is, with several different mechanisms implicated in the development of the disease.
“It’s going to take a concerted and global effort to develop life-changing treatments.
“But this seminal study also gives us hope that research will win, and it gives us the opportunity to work on new treatment targets.”
The new research has some limitations, one of which is that the genes analysed were from primarily Caucasian populations.
Therefore, the results may be of limited use for other groups.
This is something the researchers say they wish to expand upon in further studies.
Around 850,000 Britons and 5.8million Americans have Alzheimer’s disease.
Alzheimer’s is characterised by the build-up of toxic proteins in the brain that cause cells to die and for parts of the organ to shrink.
Alzheimer’s disease is most common in people over the age of 65, although people can develop it earlier.
While there is no cure, medications are available to combat some of the symptoms.
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