Since CD11c+ microglia are characteristically observed in several neurodegenerative diseases (Chiu et al., 2013; Holtman et al., 2015; Kamphuis et al., 2016; Remington et al., 2007; Wang et al., 2015), the CD47–SIRPα signal may be widely involved in the pathology of degenerative brain diseases through the control of the protective function of microglia. The gene discussed is CD47; the disease is neurodegenerative disease.