Regarding the pathogenesis of AD, several studies reported that MMP‐9 has either beneficial or detrimental effects on a variety of pathophysiological processes, such as mediating Aβ degradation and stimulating astrocyte activation, increasing brain‐derived neurotrophic factor level and maintaining synaptic plasticity, as well as regulating neuroinflammation.31 The gene discussed is MMP9; the disease is Alzheimer disease.