Early symptoms of AD were observed in mice deficient in neprilysin (a major Aβ-degrading enzyme) and ATP binding cassette subfamily C member 1 (ABCC1, a major transporter for Aβ clearance) [20], and the mice developed various aspects of sporadic AD, including astrogliosis and early synaptic degeneration [21]. The gene discussed is MME; the disease is Alzheimer disease.