lifetime risk of AD of approximately 30 percent, whereas the risk of AD is only 9 percent in people who carry no E4 allele (Post et al. 1997). However, most people who carry an E4 allele will never manifest the disease, and other people without an E4 allele can still develop AD. For this reason, screening people for the ApoE gene to determine their risk for AD has not been widely accepted in clinical practice, particularly for people who show no symptoms of the disease.
