Furthermore, 23 differential proteins (genes name: ATP5A1, ATP5B, ATP5F1, COX5B, COX6B, CYCS, LOC100524613, LOC100525869, LOC733678, NDUFA10, NDUFA12, NDUFA8, NDUFA9, NDUFB10, NDUFB4, NDUFC2, NDUFS1, NDUFS2, NDUFS3, NDUFS7, NDUFV1, SDHA, SDHB) which are involved in brain diseases such as Huntington's disease, Parkinson's disease, and Alzheimer's disease (Figure 5) were selected. The gene discussed is NDUFS2; the disease is Alzheimer disease.