Despite the single amino change between isoforms, different APOE genotypes have been implicated in a multitude of altered biological functions, including altered immune and lipid binding and altered signaling, and are associated with increased risk of multiple diseases such as Alzheimer’s disease (AD) and cardiovascular disease (CVD) (3, 5, –, 7). Here, APOE is linked to early-onset autosomal dominant Alzheimer disease.