NOS2 and early-onset autosomal dominant Alzheimer disease: New studies suggest that lead exposure activates microglia (Kumawat et al., 2014) and causes excessive production of pro-inflammatory proteins like inducible nitric oxide synthase (iNOS), interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α), which are largely attributed to neurodegeneration in Alzheimer’s disease (Zhang et al., 2017).