Blood test could detect Alzheimer's early in people with Down syndrome
Researchers have found that two automated blood tests can accurately detect early signs of Alzheimer's disease in adults with Down syndrome, Qazinform News Agency correspondent reports.
The exploratory study analyzed blood samples from 39 adults with genetically confirmed Down syndrome aged 25 to 55 who were enrolled in the NIH Trial Ready Cohort for Down Syndrome (TRC-DS). None of the participants had dementia, although some had mild cognitive impairment. Researchers compared blood test results with brain amyloid PET scans, which are commonly used to detect the buildup of amyloid, a hallmark of Alzheimer's disease.
People with Down syndrome have a much higher risk of developing Alzheimer's disease because they carry an extra copy of chromosome 21, which contains the APP gene involved in amyloid production. As new treatments targeting amyloid become available, researchers say accessible methods for identifying the disease at an early stage are increasingly important.
The team evaluated two fully automated blood tests that measure the protein phospho-tau217 (p-tau217): Fujirebio's Lumipulse immunoassay and C2N Diagnostics' PrecivityAD2 mass spectrometry assay. Both tests performed well in distinguishing participants with elevated brain amyloid from those without it. The Lumipulse test achieved an area under the curve (AUC) of 0.94, while the PrecivityAD2 test reached 0.91, indicating high diagnostic accuracy.
Using optimized thresholds, the blood tests correctly identified amyloid-positive participants with about 88% sensitivity. Specificity reached 90% for the Lumipulse assay and 94% for the PrecivityAD2 test, while overall accuracy was 90% and 92%, respectively. Researchers found no significant difference in performance between the two platforms.
The study also found that p-tau217 was a much better indicator of Alzheimer's-related brain changes than blood measurements of amyloid proteins Aβ42 and Aβ40, which showed little association with amyloid detected by PET scans in this group.
The researchers cautioned that the findings are preliminary because the study included only 39 participants, eight of whom had elevated brain amyloid. They said larger studies will be needed to confirm the results, refine testing thresholds specifically for people with Down syndrome, and evaluate how well the blood tests predict future cognitive decline.
Earlier, Qazinform News Agency reported that a groundbreaking study from Japan introduced the possibility of eliminating the genetic cause of Down syndrome.
