APOE and Alzheimer disease: Two subtypes that were identified included the Cortical Predominant+ (younger, fewer APOE ɛ4 carriers, executive function impairment) and Limbic Predominant frontal (older age, more APOE ɛ4 carriers), which align well with the Cortical Predominant and Limbic Predominant subtypes, respectively, identified by Levin et al. 11 Together, these two studies indicate the clear presence of distinct cortical- and limbic-predominant profiles of hypometabolism in AD.