Prominent examples include irisin (173), IL-6 (174), CTSB (175), and glycosylphosphatidylinositol-specific phospholipase D1 (GPLD1) (176), which have been shown to enhance BDNF expression, promote synaptic plasticity, and facilitate Aβ clearance, thereby attenuating AD pathology. Here, BDNF is linked to Alzheimer disease.