APP and dementia: Potential new disease modules include other relevant dementia risk genes, and can be related for example to relevant loss of function of proteins such as AβPP, Aβ, other AβPP cleavage products (e.g., soluble AβPP alpha and AβPP-intracellular domain), and PSEN1 which have essential physiological roles in synaptic plasticity, hippocampal neurotransmitter release (e.g., soluble Aβ-mediated activation of α7-nicotinic acetylcholine receptors), as well as maintenance of metal ion homeostasis [58, 59].