Even dominantly inherited AD (caused by pathogenic variants in APP, PSEN1, and PSEN2 genes), which is generally considered a “pure” form of AD, shows heterogeneity between cases and often includes Lewy body pathology (intraneuronal aggregates of alpha‐synuclein) and TAR DNA binding protein 43 (TDP‐43) pathology (intracellular aggregates of TDP‐43).1, 2. The gene discussed is APP; the disease is Alzheimer disease.