APP and Alzheimer disease: The link between the pathogenesis of AD and the membrane lipids had faded into oblivion for a considerable time, overshadowed by the attention to the Aβ family peptides and other products of amyloid precursor protein (APP) cleavage by secretases, but the recognition of the strong and multifaceted interrelations between the composition of the lipid membranes and the disease occurrence and progression has been growing stronger lately.