Study Identifies Protein in the Blood That May Predict Alzheimer's

A study published in the Journal of Experimental Medicine has discovered a type of protein in the blood that could help predict Alzheimer's disease, which could potentially enable experts to diagnose the disorder long before symptoms manifest, reports Medical News Today . The researchers said tau proteins are usually present in the cerebrospinal fluid surrounding the brain and spinal cord of someone with Alzheimer's, and their theoretical detection via a blood test could indicate that a person has a "preclinical" case of Alzheimer's. The authors analyzed brain scans and blood samples from 34 people — including 19 with no amyloid in their brains, five with amyloid but with no cognitive symptoms, and 10 with amyloid and cognitive symptoms. A specific tau variant — phosphorylated tau 217 — correlated with the amount of amyloid proteins in a person's brain. The presence of amyloid in the brain means someone is about two or three times more likely to have tau in their blood, regardless of whether they were cognitively symptomatic of Alzheimer's or not. A second test of 90 participants — 42 with no amyloid in their brains, 20 with amyloid but no cognitive symptoms, and 30 with both amyloid and cognitive symptoms — showed clear correlation between the phosphorylated tau protein in the blood and amyloid protein in the brain, with the former predicting the latter with 90 percent accuracy. The specific tau protein blood test identified individuals with amyloid in their brains with 86 percent accuracy.