APP and neurodegenerative disease: Nevertheless, the human genetic and pathological findings that patients with genetic alterations in the APP, PSEN1, and PSEN2 genes that drive Aβ deposition, also predispose patients to develop αSyn pathology, provide strong evidence of collusion between aberrant Aβ accumulation and αSyn, in the pathobiology of neurodegenerative diseases [12, 24–27].