In the case of AD, this consists of extracellular plaques composed of Amyloid β (Aβ), a ∼40 residue peptide derived from the integral membrane protein APP, while Dementia with Lewy Bodies (DLB) is characterized by extracellular inclusions composed of α-synuclein in addition to tau tangles. This evidence concerns the gene MAPT and Lewy body dementia.