However, tau is not specific to AD pathology, and blood tau levels have been shown to be increased in other CNS pathologies, such as traumatic brain injury and cerebral infarction (Bielewicz, Kurzepa, Czekajska‐Chehab, Stelmasiak, & Bartosik‐Psujek, 2010; Liliang et al., 2010). This evidence concerns the gene MAPT and Alzheimer disease.