Astrocyte reactivity indicated by increased GFAP expression is one of the characteristics that allow AD‐demented cases to be distinguished from those who are clinically non‐demented while having AD‐like pathology (Barroeta‐Espar et al., 2019; Perez‐Nievas et al., 2013), and evidence suggests that this astrocyte reaction precedes Aβ and tau deposition in the human brain (Carter et al., 2012; Rodriguez‐Vieitez et al., 2016). Here, MAPT is linked to Alzheimer disease.