Finally, the expressions of several newly identified neurotransmitters and neurological disease-related proteins also altered significantly, including hippocampal cholinergic neurostimulating peptide (PEBP1), fibroblast growth factor (FGF1), thymopoietin (THBS1), the amyloid-beta (Aβ) A4 precursor protein-binding family B member 1 (APBB1) and apolipoprotein E (APOE) in AD [33–36], Huntingtin protein (HTT) in HD [37], along with the protease inhibitor cystatin C is in epilepsy [38]. Here, APOE is linked to Alzheimer disease.