To follow this line, we conduct ABCA1, ABCB7, ABCB1, APOE, CYP46A1, and LRP1 genotyping to compare allele frequency in three groups of patients diagnosed with (1) dementia with coexisting hyperlipidemia or (2) hyperlipidemia, or who were (3) healthy controls, to clarify their role in dementia development and assess their potential for use as early markers of dementia among patients with dyslipidemia. The gene discussed is ABCA1; the disease is hyperlipidemia.