HSP90AA1 and Alzheimer disease: While the determination of anti-eTG and anti-tTG autoantibodies was shown to be a primary strategy used to support the diagnosis or activity monitoring of DH (specificity >90–95%) (8), we believe that the assessment of Hsp90α levels may help the physician distinguish DH from AD in those cases where serological results regarding the level of anti-eTG and anti-tTG autoantibodies are equivocal with a simultaneous low level of circulating Hsp90α.