RAB5A and Alzheimer disease: Another mechanism pointed to increased levels of the amyloid precursor protein (APP) beta‐C‐terminal fragment (β‐CTF) interacting with the APPL1 (the adaptor protein containing a pleckstrinhomology [PH] domain, phosphotyrosine binding [PTB] domain, and leucine zipper motif 1) scaffolding protein to increase RAB5 binding and activity on EEs in sporadic AD, familial AD (FAD), or DS‐AD.15, 16, 17, 18, 19