But even this narrow commonality is rather superficial: whereas in the ACH, AD is caused by extracellular Aβ produced and secreted in the Aβ protein precursor (AβPP)-proteolytic pathway, in the ACH2.0, the disease is triggered by AβPP-derived intraneuronal Aβ (iAβ) accumulated to sufficient levels and is driven by iAβ generated independently of AβPP. The gene discussed is APP; the disease is Alzheimer disease.