To determine whether there are changes in tau transport and production rates during the progression of AD, we apply our model to three groups representing different stages of the AD timeline [33, 34]: (i) A+T+: Aβ positive, tau positive; (ii) A+T−: Aβ positive, tau negative; (iii) A−T−: Aβ negative, tau negative. The gene discussed is MAPT; the disease is Alzheimer disease.