The risk of Alzheimer's disease (AD) was observed at HLA‐DRB1*15:01, HLA‐DQA1*01:02, and HLA‐DQB1*06:02 and the haplotype composed of them (DR15),46 but they were not associated with PD risk even in the study‐wide significance level (P > 3.3 × 10−6). Here, HLA-DRB1 is linked to Alzheimer disease.