APLNR and early-onset autosomal dominant Alzheimer disease: Here we focus on apelin receptor (APJR), a class A (rhodopsin-like) G-protein coupled receptor (GPCR) as apelin could be involved in preventing the production of Aβ and the accumulation of other proteins involved in the development of Alzheimer’s disease [6] and the observed high presence in the central nervous system (CNS).