Alzheimer’s disease (AD) is a multifactorial disease, in which genetic factors account for 70 percent of its causes. There are two types of AD: familial and sporadic AD. Genes of familial AD are related to family history; while that of sporadic AD, the apolipoprotein E4 (ApoE4) gene allele, is the most significant genetic risk.
ApoE gene has three forms—E2, E3, and E4. The E2 form performs a protective function as it can protect the carrier from AD incidence; the E3 form is the most common, it presents in the average population and is not related to AD; and the E4 form is a risk factor that increases the incidence of AD.  …