Several evidences implicate S100B in AD pathogenesis: it is systematically elevated in AD patients and animal models (Sheng et al., 1994; Van Eldik and Griffin, 1994; Peskind et al., 2001), it is present in elevated amounts in astrocytes surrounding neuritic plaques preceding their appearance (Sheng et al., 2000) and is suggested to regulate plaque formation. The gene discussed is S100B; the disease is Alzheimer disease.