The PHGDH gene is responsible for the production of RNA and proteins that are critical for brain development and function, which typically declines with age. In a recent study, researchers found that a sharp change in this RNA production later in life may precede Alzheimer’s disease diagnosis by up to two years. The finding suggests that a blood test for these biomarkers may help identify Alzheimer’s disease patients before they begin showing symptoms. Current Biology, March 2020