HSP90AA1 and Alzheimer disease: Although serum concentrations of Hsp90α in patients with DH (n = 26) or CD (n = 15) and healthy controls (n = 55) remained unchanged, we found that serum levels of Hsp90α were significantly higher (5.08-fold; p < 0.0001) in patients with AD (n = 31) when compared to patients with DH (Figure 1).