NOS2 and early-onset autosomal dominant Alzheimer disease: Microglial cells, the monophagocitic cells of the CNS, respond to an inflammatory stimulus inducing the expression of iNOS that causes an increase in NO levels; this mechanism has been claimed as responsible for the pathogenesis of several neuropathologies, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis [5].