While many but not all researchers postulate that an aggregated form of the amyloid-beta peptide is involved in the development and potential treatment and prevention of Alzheimer’s disease and recent trial findings have raised the possibility that amyloid-beta plaque-reducing antibodies may slow clinical progression in symptomatic people, the roles of amyloid-beta and APP in the development and potential treatment and prevention if AD needs to be clarified and confirmed in additional studies. The gene discussed is APP; the disease is Alzheimer disease.