The NACC dataset is enriched for subjects with Caucasian ancestry, high levels of education, rare diseases/pathologies, more frequent APOE ε4 alleles, more severe dementia, and more severe neuropathologic findings, which may be related to population-specific selection and recruitment biases, including enrolling a higher number of patients with existing dementia compared to cognitively normal individuals [24, 86]. The gene discussed is APOE; the disease is dementia.