The HPA axis’s overproduction of cortisol affects somatic tissues through blood flow, and elevated levels of GC, including cortisol, lead to hemodynamic, endocrine, and immune system problems as well as increased accumulation of Aβ and tau, which cause increased brain atrophy, behavioral deficits, mood disorders (Du and Pang, 2015), and/or cognitive decline (Milligan Armstrong et al., 2021), all of which accelerate the progression of AD and PD (de Pablos et al., 2014; Ennis et al., 2017). Here, MAPT is linked to Alzheimer disease.