Matrix metalloproteinase-9 (MMP-9) is a zinc-dependent enzyme, that belongs to the family of MMPs and contributes to the neuroinflammatory response in neuroinflammation and in neurodegenerative diseases such as amyotrophic lateral sclerosis [10], and Alzheimer's disease [11,12]. Here, MMP9 is linked to early-onset autosomal dominant Alzheimer disease.