In reality, in vitro, analogs of humanin, an endogenous agonist of the heterotrimeric humanin receptor, suppress all kinds of AD-related neuronal death, induced by high concentrations of Aβ and ectopically expressed familial AD-causative mutants of amyloid-β precursor protein and presenilin 1 and 2 [(14) for review]. Here, MT-RNR2 is linked to Alzheimer disease.