Using linear regression analysis, seven proteins (APOA1, alpha-1 antitrypsin [A1AT], ApoC3, brain-derived neurotrophic factor [BDNF], AB40, plasminogen activator inhibitor-1 [PAI-1], and NSE) in the AD group were able to predict 11.9% (P = .039) of hippocampal volume. This evidence concerns the gene SERPINA1 and Alzheimer disease.