CD33 and Alzheimer disease: Comparison against a threshold of 0.05/101 = 4.95 × 10–4 in the microglial module revealed that the significant genes associated with AD were membrane spanning 4-domains A4A (MS4A4A), human leukocyte antigen-DR alpha (HLA-DRA), triggering receptor expressed on myeloid cells 2 (TREM2), human leukocyte antigen-DR beta 5 (HLA-DRB5) and cluster of differentiation 33 (CD33) in both AD GWAS summaries (Supplementary Table 9).