On the other hand, the myelin model of the human brain proposed by Bartzokis (Bartzokis, 2011) considers AD as homeostatic responses to age‐related myelin breakdown, and a key protein of AD (i.e., Aβ and tau) is a byproduct of the myelin repair process rather than the primary cause of AD. The gene discussed is MAPT; the disease is Alzheimer disease.