RCAN1 and Dravet syndrome: Among those genes, APP is involved in Alzheimer Disease, which as we already stated has an early onset in DS patients [146, 147]; SYNJ1/synaptojanin regulates neurotransmission together with two other HSA21 genes, intersectin/DAP160 and RCAN1 [148], and is involved in learning and memory; Tiam1 and Ttc3 are involved in neurogenesis [149]; and NRIP1 is needed for cognition and recruits HDACs [150] (Figure 3(b)).