INS and Alzheimer disease: This may interfere with the insulin signaling pathway and impair glucose uptake in the brain with DS, causing the brain to become insulin resistant and hamper the physiological functions of insulin, such as neurite growth, promoting dendritic spine formation, development of excitatory synapses, and promoting neuronal survival by inhibiting apoptosis; leading to the development of neuropathology like AD in young individuals with DS (Ogihara et al., 1997; Tramutola et al., 2020) (Figure 3B and Table 1).