In this context, astrocytes are shown to play an important part in the formation of Aβ plaques by producing the protein APOE, which has three major alleles, known as ε2, ε3, and ε4, with different effects on cognitive function, with ε4 being the most well-established genetic risk factor for late-onset AD [36], whereas ε2 exhibits the greatest protection and a lower risk of AD [37]. The gene discussed is APOE; the disease is Alzheimer disease.