APOE and early-onset autosomal dominant Alzheimer disease: This age-related allelic difference in methylation level may provide mechanistic support for previous findings linking the A allele of rs405509 to greater risk of myocardial infarction (Lambert et al., 2000), premature coronary heart disease (Viitanen et al., 2001), and Alzheimer's disease (Lambert et al., 1998), but lower plasma concentration of ApoE (Lambert et al., 2000).