To this end, our comparative analysis identified some of our core set genes (Atp6ap1, Atp6v1c1, Cox4i1, Cox7a2, Cs, Gpi1, Sucla2, Uqcrc1) were significantly down-regulated in the cerebral cortex of Tg2576 mice during the earliest pre-symptomatic stages, supporting their potential role in early-stage AD diagnosis [24]. The gene discussed is PIGQ; the disease is Alzheimer disease.