Scientists may be one step closer to a cure for Alzheimer’s disease after figuring out who is most likely to get the disease.
Researchers have found that almost all individuals with two copies of a certain gene called APOE4 develop signs of the memory-robbing disorder.
The quirk – worn by Avengers star Chris Hemsworth – was previously linked to a tenfold increased risk.
The team from the Sant Pau Research Institute in Barcelona analyzed clinical data from more than 10,000 people and more than 3,000 brain donors.
They found that more than 95 percent of people aged 65 and older who had two copies of the APOE4 gene showed early signs of the disease.
Researchers have found that almost all individuals with two copies of a certain gene called APOE4 develop signs of the memory-robbing disorder. The quirk – worn by Avengers star Chris Hemsworth – was previously linked to a tenfold increased risk
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss
These people also developed the condition earlier than people with other variants of the gene, researchers said.
They believe this is the first study to show that having two copies of APOE4 virtually guarantees the onset of the disease.
The team said their discovery is especially important because about 2 percent of the population carries two copies of this gene.
And it could determine which people are best included in clinical trials for treatment.
Dr. Juan Fortea, director of the neurological diseases, neurosciences and mental health research area at the Sant Pau Research Institute, said: ‘These data represent a reconceptualization of the disease or of what it means to be homozygous for the APOE4 gene.
‘This gene has been known for more than thirty years and was known to be associated with a higher risk of developing Alzheimer’s disease.
‘But now we know that virtually all individuals with this duplicated gene develop Alzheimer’s biology.’
The APOE gene exists in three different variants: APOE2, APOE3 and APOE4.
Everyone carries two copies of APOE, one inherited from each parent. Previous studies have shown that having at least one APOE4 gene variant, which around a quarter of people in Britain are thought to be carriers, almost triples the risk of getting the disease.
The new research found that almost all people who had two copies of APOE4 by age 65 had abnormal levels of a protein known as amyloid in the fluid surrounding the brain and spinal cord – a key sign of Alzheimer’s disease .
Dr. Reisa Sperling, professor of neurology at Harvard Medical School, and director of the Center for Alzheimer Research and Treatment at Brigham and Women’s Hospital in Boston, Massachusetts, said: ‘We need to think about how to treat APOE4 carriers.
“These individuals are desperate; they have seen it (the disease) in both their parents.
‘This research really suggests that we need to treat them very early, at a younger age and at an early stage of the pathology, because we know they are likely to progress to disability quickly.’
Commenting on the findings, Professor Tara Spires-Jones, President of the British Neuroscience Association, said: ‘This study adds compelling data suggesting that people with two copies of this gene are almost guaranteed to develop Alzheimer’s if they live long enough and that they will. are more likely to develop Alzheimer’s disease than people without this gene.
‘Going forward, these and other studies highlight the importance of more basic research into understanding how genes change our brain’s susceptibility to Alzheimer’s disease as we age.’
Professor Jonathan Schott, Chief Medical Officer at Alzheimer’s Research UK, also said the charity is currently funding research projects to try to understand why having the APOE4 gene increases the risk of disease.
“We currently do not recommend that people have genetic testing for APOE unless they are participating in research, but this may change in the future,” he added.
The study was published in the journal Nature Medicine.
It is thought that around 944,000 people in Britain are living with dementia, while in the US the figure is around 7 million.
Alzheimer’s disease affects about six in ten people with dementia.
It is thought to be caused by a buildup of amyloid and tau in the brain, which clump together, and by plaques and tangles that make it harder for the brain to work properly.
Eventually, the brain struggles to cope with this damage and dementia symptoms develop.
Memory problems, thinking and reasoning problems, and language problems are common early symptoms of the condition, which then worsen over time.
An analysis by Alzheimer’s Research UK found that 74,261 people died from dementia in 2022, up from 69,178 a year earlier, making it the country’s biggest killer.