50 Percent of Alzheimer’s Cases Due to Gene Allele, Lifestyle Factors Key for Prevention

Although only about 20 percent of the human population carries ApoE4, it accounts for an estimated 40 to 65 percent of Alzheimer's disease (AD) cases. Kateryna Kon/Shutterstock

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.