Those not encoded by Hsa21 included 20 and 14 components of the MAPK and MTOR pathways, respectively, 14 subunits of glutamate receptors and their interaction partners, 7 proteins involved in apoptosis or inflammation, four immediate early gene (IEG) proteins, three histone modifications, and 12 related to abnormalities seen in brains of Alzheimer’s Disease (AD) and/or mouse models of AD. Here, MTOR is linked to early-onset autosomal dominant Alzheimer disease.