CD33 and Alzheimer disease: Furthermore, the gene CD33, which belongs to the sialic-acid-binding immunoglobulin-like lectin family, has been reported as a strong genetic locus associated with AD by GWASs (Bertram et al., 2008; Hollingworth et al., 2011; Naj et al., 2011) and has been suggested to impair the microglia-mediated Aβ clearance (Bradshaw et al., 2013; Griciuc et al., 2013; Jiang et al., 2014).