Genetic cause for Alzheimer’s could help treatment
Researchers have identified a genetic trait that makes it virtually “guaranteed” a person will get Alzheimer’s in a discovery that may open the way to better targeted treatments and earlier diagnoses.
A study found that having two copies of a specific gene meant it was almost inevitable a person would develop symptoms. The discovery may help the development of targeted treatments and could enable genetic testing and earlier interventions.
More than 900,000 people have dementia in Britain, the majority with Alzheimer’s. There is no cure, although treatments can slow its progress.
In the study, researchers in Barcelona found that 95% of people over 65 with two copies of the APOE4 gene variant developed signs of the disease. About one in four people in Britain have one copy of this gene and one in 50 – equivalent to more than a million people – have two.
“This gene has been known for over 30 years and it was known to be associated with a higher risk of developing Alzheimer’s disease,” said Dr Juan Fortea, lead author of the study.
“But now we know that virtually all individuals with this duplicated gene develop Alzheimer’s biology.”
The researchers said their findings amounted, in effect, to the discovery of a new genetic form of the disease, because the presence of both genes was such a useful predictor of the condition.
The findings, published in the journal Nature Medicine, are based on data from more than 10,000 people and more than 3000 brain donors.
Sian Gregory, of Britain’s Alzheimer’s Society, said: “I think it’s definitely a breakthrough for the field in terms of how we think about the causes of Alzheimer’s disease.”
She said it would make it easier to predict when symptoms might start.
Previous studies have shown that having at least one APOE4 gene variant almost triples the risk of getting the disease and having two copies increases the risk by up to twelvefold.
In the latest research, a majority of people with two copies of APOE4 showed some signs of the disease by the age of 55.
At 65 years old, 95% of them had abnormal levels of a protein known as amyloid in the fluid that surrounds the brain and spinal cord – a key sign of Alzheimer’s. –