The chosen proteins Apolipoprotein E (APOE), Amyloid Beta Precursor-Like Protein (APLP), Claudin-5 (CLDN5), Superoxide Dismutase (SOD), Matrix Metalloproteinase-9 (MMP-9), and Methylenetetrahydrofolate Reductase (MTHFR) play a key role in the progression of vascular dementia. The gene discussed is MMP9; the disease is vascular dementia.