Scientists have come up with a new method to identify people with a higher genetic risk of developing Alzheimer’s disease before any symptoms appear. The research, published this Thursday, 1st, opens the way to accelerate the creation of new treatments and improve the screening and diagnosis of patients.
Alzheimer’s is a neurodegenerative disease characterized by impaired memory and the ability to perform everyday tasks. Clinical diagnosis usually occurs late (when the patient already has memory lapses), although the mechanisms of action of the disease are present years before the appearance of the first symptoms.
The available treatments, in turn, still do not have good results in reversing the damage caused by Alzheimer’s. Scientists around the world have been looking for answers to speed up the diagnosis of Alzheimer’s and offer drugs capable of halting the progression of the disease or slowing its progression.
One of the fronts of scientific action is genetic analysis. Previous research had already identified three genes that would be responsible for the development of a rare, early-onset form of Alzheimer’s. Scientists have expanded genetic scanning to create a polygenic score for Alzheimer’s – that is, an estimate, based on genetic variants, that the disease appears.
The research was carried out by scientists linked to the Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard University, in the United States, and published in the scientific journal PLOS Genetics.
The researchers analyzed data on 7.1 million DNA sequence changes obtained in a previous study of thousands of people with and without Alzheimer’s. They used this data to develop a new method that predicts a person’s risk of developing Alzheimer’s depending on which DNA variants they have. Then, they refined and validated the method with data from another 300,000 people.
In addition, the scientists analyzed the concentration of 3,000 proteins in the blood of people classified as high and low risk on the genetic score for Alzheimer’s. The aim was to find out whether the concentration of certain proteins in the blood was higher or lower depending on the genetic risk for Alzheimer’s. That analysis revealed 28 proteins that may be linked to Alzheimer’s risk, including some that have never been studied.
Identifying proteins that may be associated with Alzheimer’s is important because this information may offer clues to the development of effective treatments. Discovering disease biomarkers could be a way to unravel the biological mechanisms of Alzheimer’s – and, consequently, advance drug research.
The data highlight the potential of a DNA-based scorecard to identify high-risk individuals during the prolonged pre-symptomatic phase of Alzheimer’s disease and to enable biomarker discovery based on the profile of young individuals at the extremes of the score distribution.” highlighted the researchers in the study.
Despite the findings’ potential for future research, the researchers urge caution in using the data. They reason that the polygenic score was determined using data from a British bank – the method may not be accurate for non-European populations.
In addition, they say, current guidelines do not recommend comprehensive genetic risk assessment for Alzheimer’s (only screening for genes linked to rare forms). In part because such an assessment can have implications such as increased anxiety, without it still being possible to offer treatment and prevention options to patients.