Diabetes mellitus (DM) is caused by dysregulation of insulin signaling, and the number of patients with DM is increasing worldwide.[1] DM is a potential risk factor for neurodegenerative diseases, including dementia and Alzheimer's disease (AD).[2] As the prevalence of diabetes increases, the number of patients developing DM‐induced neurodegenerative diseases, including AD, is getting higher.[3] Because DM‐induced AD may represent a brain‐specific form of diabetes mellitus, such phenotype is also termed “type‐3 diabetes mellitus” (T3DM).[2a,b]. Here, INS is linked to diabetes mellitus.