APP and familial Alzheimer disease: The present review analyzes the results of recent clinical trials of β secretase inhibition in sporadic Alzheimer’s disease (SAD), considers the striking dichotomy between successes in tests of β-site Amyloid Precursor Protein-Cleaving Enzyme (BACE) inhibitors in healthy subjects and familial Alzheimer’s disease (FAD) models versus persistent failures of clinical trials and interprets it as a confirmation of key predictions for a mechanism of amyloid precursor protein (APP)-independent, β secretase inhibition-resistant production of β amyloid in SAD, previously proposed by us.