Asia Post
A new kind of screening for Alzheimer's disease could enable medical professionals to determine when a patient at high risk of developing the condition could begin to experience cognitive decline, a study has found. Researchers at Columbia University found combining a blood test that measures a biomarker known as p-tau217 and a genetic test that looks for a variant of the APOE gene could enable clinicians to predict when a high-risk and currently asymptomatic patient will start to experience the signs of Alzheimer's. The study was published in the journal The Lancet Neurology on September 9.
"This is an important step forward because it shows that a blood marker of Alzheimer's-related pathology, p-tau217, contains information not only about risk but potentially about how quickly cognitive impairment may develop," Ebrahim Zandi, a professor of immunology and immune therapeutics at the University of Southern California, told Newsweek . Newsweek contacted the lead author of the study via email for comment. How Do The Tests Work?
The researchers at Columbia University reviewed the clinical data of almost 9,000 people and found that, in general, people with both higher p-tau217 levels and APOE4 appeared to have a 24 percent higher risk of progressing to Alzheimer’s disease, compared to 13 percent in people who did not carry the gene. They also found that those who already had higher p-tau217 tau levels, as well as one or more copies of the high-risk APOE4 gene, were likely to develop cognitive decline in three or four years. The blood marker p-tau217 is associated with Alzheimer's, as when the disease-related pathology develops, levels of a protein called tau in the body increases.
The particular form, p-tau217, can be measured in the blood, making it potentially useful as an early warning signal, sometimes before a person has noticeable symptoms. In regard to the genetic testing, people inherit different versions of the APOE gene, and APOE4 is associated with a greater risk of developing Alzheimer's disease and, in many people, an earlier onset, but that's not to say those carrying the APOE4 gene will definitely go on to have Alzheimer's disease. This means that p-tau217 acts like a signal of what is happening biologically, while APOE4 is part of a patient's risk background.
Zandi said the APOE4 finding is "especially interesting because it suggests that the same p-tau217 level may mean different things in people with different genetic backgrounds." "But I would be cautious about calling this an Alzheimer's 'clock'—the study predicts clinical cognitive impairment, not the exact timing of Alzheimer's disease symptoms in an individual," he said. ... What The Findings Mean The researchers said the findings could enable clinicians to identify people who are on a trajectory toward Alzheimer's-related cognitive decline before major symptoms appear, which could be particularly valuable as Alzheimer's disease develops over many years and interventions are believed to be most effective when used before substantial brain damage has occurred. Thomas Karikari, an associate professor of psychiatry and clinical and translational science at the University of Pittsburgh School of Medicine, told Newsweek that, while the findings were "encouraging," they also "point to an important caution." He said results show that these tools "may not work the same way for everyone," as the strength of the relationship between the blood test, genetic risk and Alzheimer’s progression "appeared to vary across study groups, likely reflecting differences in genetic background and racial or ethnic diversity." He added that the risk is "seemingly much more pronounced in some groups than in others, and this seems to be based on the racial and ethnic makeup of the people in those cohorts." "That is quite crucial—it means that two people who have different racial or ethnic background, but the same APOE4 genotype and the same biomarker level, may look like they have the same risk when their progression to Alzheimer’s disease would actually be very different," he said.
Therefore, Karikari said the findings show "risk prediction is not one size fits all. We need studies with more diverse populations to help these tools give accurate risk assessment in all patients, without underestimating risk for some people while overstating it for others." Reference Xu Y, Gunasekaran T, Gu Y et al. (2026) Plasma phosphorylated tau 217 concentrations, APOE genotype, and timing of cognitive impairment in individuals across diverse racial and ethnic groups: a pooled analysis of prospective cohort studies. The Lancet Neurology . https://doi.org/10.1016/S1474-4422(26)00313-3 Contact Newsweek editors on this story: Kara Dolman and Emma Lee-Sang
Source: Newsweek
