MAPT and early-onset autosomal dominant Alzheimer disease: Type 2 DM can influence the risk of Alzheimer's disease in the following ways: (1) type 2 DM can give rise to small blood vessel disorders, which can cause dementia, independent of or along with Alzheimer's disease pathology, by disturbing the appropriate functioning of the vasculature of the brain [18], and (2) type 2 DM produces alterations in the brain function directly or interact with the essential proteins or pathways associated with the pathology of Alzheimer's disease, such as tau or Abeta.