GFAP and early-onset autosomal dominant Alzheimer disease: This aggregation leads to BBB leakage, vessel occlusion or rupture, collectively worsening Alzheimer’s disease symptoms and cerebral impairment.133 The glymphatic system, a structured network involving astrocytes, may also provide a route for GFAP to enter the circulation.134 This system is essential for clearing the brain of metabolic waste and potentially harmful substances.