The role of CD33 in AD is further affirmed by positive colocalisation between the cis-pQTL with the causal variant rs2455069 (MAF = 0.3967; P = 2.03 × 10−1580; BETA = 1.2092; SE = 0.0142), and a known AD-associated locus (CLPP4 = 0.82). Here, CD33 is linked to Alzheimer disease.