In addition, the interaction between APOE and SIRT1 may also have an impact on individual’s obesity and cognition56, for instance, Jesus Campagna et al.57 found that the expression of APOE E4 would decrease the level of SIRT1 in serum and brain tissue of AD patients as compared to normal controls; Veena et al.58 found that APOE E4 could reduce the expression of SIRT1 expression and thus played a neuroprotective role; what’s more, María Teresa Flores-Dorantes et al.59 also found that SIRT1 gene could be affected by APOE gene, and then regulated obesity. The gene discussed is SIRT1; the disease is obesity due to melanocortin 4 receptor deficiency.