In AAV-αSyn PD mice, no differences in [11C]HSP990 binding were observed between ipsilateral and contralateral brain sides or in Hsp90α/β expression, despite confirmed dopaminergic neuronal cell death (40%) and evident pSer129-αSyn pathology in affected regions (Fig. 2; Supplemental Figs. 12 and 15). This evidence concerns the gene HSP90AA1 and Parkinson disease.