‘Landmark’ Alzheimer’s study could lead to better diagnosis and treatment
For the first time, more than 40 genes have been linked to Alzheimer’s disease in a ‘landmark’ new study that could pave the way for better diagnosis and treatment.
Scientists from around the world, including the UK, have carried out the largest research project of its kind on the genomes of more than 100,000 people with Alzheimer’s disease.
The results suggest that the disease is caused by a multitude of different factors and provide new evidence for the role of a specific protein involved in inflammation.
The team hopes that in the future they will be able to determine what factors put people at risk for developing Alzheimer’s disease and develop therapies that better treat the disease.
Genetic testing could help identify those at risk
Genetic testing could also identify people most at risk of developing Alzheimer’s disease before their symptoms start to appear.
The study, published in Nature Genetics, identified 75 genes associated with an increased risk of developing Alzheimer’s disease, including 42 genes not previously implicated in the disease.
It also confirmed previous findings about beta-amyloid and tau proteins, which accumulate in and around nerve cells as Alzheimer’s disease progresses, and revealed that inflammation and the immune system play a role in disease.
A group of 111,326 people with Alzheimer’s disease was compared to 677,663 healthy individuals to look for differences in their genetic makeup.
For the first time, the results showed that a specific biological signaling pathway involving TNF-alpha (a protein playing an important role in inflammation and the immune system) is involved in Alzheimer’s disease.
Research has also provided more evidence that dysfunction of microglia (immune cells in the brain responsible for eliminating toxic substances) contributes to disease progression.
Ongoing and upcoming studies will now look at genes and their involvement in brain cell death, which could lead to new treatments.
A genetic risk score was also created to determine the likelihood that patients with cognitive impairment will develop Alzheimer’s disease within three years of the onset of symptoms.
Professor Julie Williams, Center Director at Cardiff University’s UK Dementia Research Institute and co-author of the study, said: “This is a landmark study in the field of disease research. Alzheimer’s disease and the culmination of 30 years of work.
“Genetics is helping us and will continue to help us identify specific disease mechanisms that we can target therapeutically.
“This work is a big step forward in our mission to understand Alzheimer’s disease and ultimately produce several treatments needed to delay or prevent the disease.
“The results confirm our growing knowledge that Alzheimer’s disease is an extremely complex disease, with multiple triggers, biological pathways and cell types involved in its development.
“Components of our immune system have a big role to play in disease development.
“For example, immune cells in the brain known as microglia are responsible for clearing away damaged tissue, but in some people they may be less effective, which could accelerate disease.
“Lifestyle factors such as smoking, exercise and diet influence our development of Alzheimer’s disease, and taking action to address them now is a positive way to reduce our own risk.
“However, 60-80% of disease risk is based on our genetics and so we must continue to search for biological causes and develop much-needed treatments for the millions of people affected around the world.”
Dr Rebecca Sims, principal investigator at Cardiff University and co-investigator of the UK Dementia Research Institute, and co-lead on the research, said: “This study more than doubles the number of identified genes influencing the risk of the most common form of Alzheimer’s disease.
“It provides exciting new targets for therapeutic intervention and advances our ability to develop algorithms to predict who will develop Alzheimer’s disease later in life.”
Eight countries, including the UK, the US and Australia, participated in the study.
Alzheimer’s disease is the most common cause of dementia and affects over 850,000 people in the UK alone.