Three main changes in the basement membrane have been described in AD: (1) Aβ deposition in the walls of the cerebral vasculature (known as cerebral amyloid angiopathy), which occurs in approximately 80% of AD cases; (2) basement membrane thickening in capillaries of AD patients and AD animal models; and (3) altered distribution of basal membrane proteins such as collagen IV, fibronectin, and perlecan; however, the changes in these proteins are inconsistent [26]. Here, HSPG2 is linked to Alzheimer disease.