ApoE‐ɛ4 allele might be involved in almost all AD pathological processes, including amyloid beta (Aβ) aggregation, neurofibrillary tangle formation, cholinergic activity, cholesterol metabolism, synaptic integrity, and plasticity (Kotze et al., 2015; Safieh et al., 2019). The gene discussed is APOE; the disease is Alzheimer disease.