The hippocampal expression of both CXCL12 and CXCR4 were decreased in Tg2576 mice at 6 and 12 months of age as compared to age-matched non-transgenic animals; this was paralleled with cognitive impairment (Parachikova and Cotman 2007). The gene discussed is CXCR4; the disease is Cognitive impairment.